well.. I don't know too much about preludes - just got one.. but I'll try to help. If I'm wrong, please correct me

the 3rd (89-91?) and 4th gen (92-96) preludes had an s, si, and vtec model. The s was the base model.. which came with hubcaps, less hp, etc. The si was better, and had alloys, with a bigger engine.. I believe around 127hp.. but a sohc engine. The vtec had the best engine and it was dohc with around 195hp I think. The 5th gen preludes (97-2001) only came in two models, the base, and the SH. They both have the same engine - dohc with around 200hp. The base came with alloys, and pretty much all the goodies, however the SH had slightly different wheels, weighed about 90 lbs more than the base, and had ATTS - which stands for automatic torque transfer system i believe - it helps the car handle better around turns at higher speeds from what i understand - and makes it better to race/more like rear wheel drive cars (as far as turning goes)

This is about all I know.. and like I said, i'm not sure it's even right, lol (please dont yell if it's not :-/) But I AM trying to learn, since I do have a prelude now. i liked them before, and now i figure i should try to learn more about them But one thing i AM sure of.. I have a 5th gen SH and I love it