With a B16a2 swap it will. DOHC
The EX is a D16 SOHC. just a ecu swap will not work.
It wont evan start right.
Do you intend to build this car up?
or just goff arround?
The SI has:
B16a2 1.6l DOHC VTEC 160hp
15" wheels
4 wheel disk brakes
larger frunt rotore then EX
Stiffer suspension coilovers
Comptech struttower bar (Identical)
145mph spedo (intake, header and exhaust can do)
Orange gage cluster.
Lower lip kit
Flood loights in some
I had a 99SI with:
AEM V@ cold air intake
DC sports 4-1 header
Skunk2 Full cat back
skunk 2 frunt and rear upper strut tower bars
Power slott rotors in the frunt and AEm pad all arround.
Denso iridum plugs
New oem fuel filter
Royal purple oil. 93 oct only with ocational 10octane boost
I did the Sea Foam treatment to clean the head from the inside out.
It ran sweet all the way to 8300rpm fuell cutoff.
Average price for on is now arround 6K-7K
Hard to find clean and un modified.
Pros- Great car to drive! low on gass, unequaled aftermarket support in parts and help, runs down V8s in 5th gear above 100mph
kill list:
Beat the brakes off of Storms, Probes, miatas (bad drivers), neons, stealth V6
Run down v6/v8 mustangs 110mph, BMW 325 115mph, Neon SRT 125mph.
KILLED cutlass convert V8 some sh!T

left dead on the road. LOL!!
Cons. FWD great in corners bad at the light. and every one and there mamma has a civic

.
I had an EX and traded it in for the SI better platform to start with.
Or go to the junk yards and swap out all the parts on the low.
I just didnt see the purpose in messing with a "D" series
Chose your platform
Plan your project.
Execute it quickly.
Hope I didn't over dose you.
Peace