hey guys, well about 1st gens, i have a friend that put a b16a into a 1st gen CRX Si, it is a tight fit but runs damn quick times, i think his best with i/h/e is 14.2, if u want ill ask my friends how easy it was for him and everything and see if theres any advice i can give u guys, probaly good engines are b16a ZC and b18a, but its up to u, i think b16a would be a smokin choice, b/c u guys are damn light and dont need the torque the b18a puts out, u just need the high hp of the b16a to get u going, anyway good luck and ill C what i can do.