Okay, since PM's limit you to only 1100 characters, here's my pitch. I put these into sort of "steps", how far you want to go depends on how much power you want to make and how fast you want to go.
By posting this I'm not saying I'm a know-it-all expert, I'm just giving some facts, there may be a few small inaccuracies but I'll try my best. Anybody should feel free to correct me or add to what I have said.
LS engines are not high-revving, super-high flow, high-compression engines like VTEC engines. This essentially means two things:
1. It won't have the same top-end punch as a VTEC engine with similar mods, although it CAN have more than a stock VTEC engine.
2. LS engines have the most torque of any B-series motor except the B20 (CR-V engine), so they have good punch in low to mid-range that VTEC cars typically don't have.
Stage 1: External Bolt-ons
"Basic bolt-ons", which are intake, header, exhaust, and if you're thorough a high-flow catylitic converter. On the LS, these alone don't add a whole lot of power (probably 12-18whp altogether with the right parts), but keeping these stock limits the breathing capacity of further modifications. If you get good, high-quality parts that work well in your application, your car will sound sweet and have more power all around, especially in the high-end. Bolt-ons are nice because they are relatively easy to install and they don't cause too many reliability or drivability issues. Here are some recommendations on what to get:
Intake ($170-200): AEM cold-air, Injen, Comptech Ice Box.
Header: Lower cost ($360-380) = DC Sports stainless steel header (ceramic-coated is cheaper, but is known to crack over time). A 4-1 design sacrifices a bit of low-end power for a lot of high-end, while the 4-2-1 adds decent power all around. I just installed my 4-2-1 DC header last night, very nice....
The JDM Type-R header also is very good, it's a 4-1 design and should last forever.
Higher cost ($450-1000) = Headers by high-end companies such as Mugen, Spoon, and SMSP often combine 4-2-1 and 4-1 designs to get the best of both worlds, they're pricey but do add significant power over a DC header.
Catalytic converter ($150-180 with all the flanges and hardware): Carsound seems to be the best brand, go for a diameter that matches your exhaust and header well, i.e. if you have a 2.25" header collecter and a 2.25" exhaust B-pipe, go for a 2.25" cat.
Exhaust ($400-800+): This is more up to personal preference, because of the different aural and visual characteristics of each system. You CAN go wrong here though, by getting a system that is not sized properly for your application. I love it when ricers get a huge 3" turbo exhaust (that they probably bought because it said "turbo" on it) and they lose tons of low-end power and it sounds shitty. Get a 2.25" to 2.5" for your application, it should be plenty. Also don't get some cheapass brand, get name brands like GReddy (although reliability is sketchy by my experience), A'pexi, DC Sports, 5Zigen, etc. If you want to spend a little more the Mugen system provides good gains and is relatively quiet. There are others that are good too, I'm just mentioning a few.
Aftermarket pulleys make a small difference in power, and if you need a new clutch, getting an upgraded one along with a lighter flywheel will help you shift faster, launch harder, and have more power at the wheels.
Stage 2: Deeper breathing
This step involves some more extensive modifications that are more of a bitch to install and tune, but will give you some quite meaningful gains.
Cams ($350): With cams you will need some sort of fuel delivery control, since cams give you much more air than before, I would suggest an A'pexi S-AFC ($300) or Hondata, the latter especially if you have an OBDI ('94-95) Integra. Cams will make your car idle roughly, with added vibration and a willingness to stall, but if tuned properly with the above items, it will NOT stall, it will just shake and rumble, which is sweet.
What I and many other people have found is that Crower makes some nice cams for LS engines that add that top-end kick that our cars lack somewhat when stock. Here are their models:
62401: essentially stock replacements, don't bother.
62402: Mild cams, give you a decent gain but not huge. Probably doesn't run too roughly though.
62403: My choice, and the most popular model. It idles kinda crappy and wants to stall until you tune the fuel, then it idles pretty nicely, mine hasn't stalled since nor has it tried to. A lot of people choose these cams because they are wild enough to give a very nice VTEC-like kick at high-rpms yet are docile enough to be driven daily without major sacrifices. A++ With these cams, you can buy the spring and retainer kit, which allows you to rev past the stock rev limit and make more power potentially, or stay with the stock springs/retainers and stay at the stock rev limit. If you decide to raise the redline, you should also build up and balance the bottom end (pistons, rods, etc) because the B18B isn't made for revving high stock. What many people (like me) do is run these cams with the stock springs and retainers, which Crower reps themselves said is fine to do as long as the stock rev limit is retained, I haven't heard of any problems. These cams don't make much power over the stock rev limit, so I personally choose to just stay with the stock rev limit. I may eventually pick up the springs/retainers just for reliability's sake. But for those who want more....
62404: A pretty darn extreme cam, without tuning it usually doesn't hold an idle, but once tuned carefully it can be used in daily driving. You will lose low-end power but with a raised redline and the requisite bottom-end build-up and springs/retainers, they will make significantly more high-end power than the 403's.
62405: RACE ONLY.
I could go into more detail about cams, and I will if you ask me, but this post is getting very long, so I'll go onto other stuff. Basically though, I like to think of wild cams as a sort of "amplifier" for other mods. By increasing the intake (and exhaust) of air at the source, your engine effectively "needs" flow more. It is more choked off by restrictive parts than before, so for example if you get an intake, it will make more of a difference than if you got an intake with stock cams. I remember when I had the cams put in and I still had the stock exhaust, at idle I could feel the exhaust gases shooting out from 7 feet away, that's how much exhaust gas was flowing at IDLE. Cams make every other mod more worthwhile.
Cam gears ($180-200): These adjust your cam timing, and can produce good gains with aftermarket cams as well as shift your powerband up and down, but only when they are tuned on a dyno.
Fuel computer: Hondata is a program for tuning fuel and other systems, and is superior to the A'pexi system in that it is more adjustable, I don't know a whole lot about the system but it is very nice from what I've heard. If you have a '96-'01 car however, it has an OBDII emissions system that you have to convert back to OBDI in order to use Hondata, a $200 extra cost. Which is why I went with the A'pexi S-AFC, a $300 blue-screened box that is wired into your engine computer and allows you to fine-tune the amount of fuel delivered in different rpm ranges. Very recommended if you get cams.
Intake manifold and throttle body ($300 for IM, $100-300 for TB depending on whether you bore out your existing TB or buy a new one): The intake manifold basically goes from your intake pipe to your cylinder head. In combination with the cams this will give you a decent amount of power, although I can't say I know a whole lot in this field, maybe someone else can talk about this stuff. But basically a Skunk2 intake manifold will work well for all-motor, and a bigger throttle body matched to the manifold will add power as well. Don't get a huge TB though, as it will cause you to lose some power in the rev range.
Stage 3: Internals
If you really want a badass B18B after doing cams, IM, fuel computer, etc., then putting in some high-compression pistons will add significant power, and getting stronger connecting rods will allow you to rev higher. However this involves internal work which may be difficult for you / expensive. You can also get a port and polish job done to your head, which will maximize flow if done correctly and give you excellent gains with the high-CR pistons and wild cams.
LS/VTEC : LS-VTEC is when a VTEC head (with cams, valvetrain, etc.) is put on an LS block. This setup, when done properly, can yield a lot of power, more than what is possible with an LS head, but it is very difficult to make this setup reliable because of oil passageways and other stuff. In general LS/VTEC is well respected, but risky. I would not be the one to ask about how to make your car LS/VTEC, I would say "perform at your own risk" and "you'll probably be faster than me".
I hope this wasn't too much all at once. If you have questions, feel free to ask, but do a search on the web board first.
I'm not claiming to be some expert on LS engines, I'm just speaking on personal experiences, which are limited since I have only been screwing around with my car for 2 1/2 years. So anybody else should feel free to correct me or add to what I said. Good luck!! I will probably dyno my car this weekend, I'll try to post it up or at least post what numbers I got. I'm expecting about 150-155whp and 130 or so wtq after tuning.
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Autocrossing for a day is the best $25 you can spend
I would like to rev to 9k and can safely do that with a built GSR, whereas I am unsure if the r/s ratio of the LS crank would cause issues down the road for a daily driver... I like me some revs