its not that heavy, i have a 4th gen, and they weigh in at about 2866lbs, where as the 99-00 civic si is around 2600. Also, there are many upgrades you can do, its just a little harder to find. Dropping in a v6 in all honesty wouldnt be smart. To much money and in the end you could probably squezze better numbers out of the h22a.