Question about S13 vs S14..

What exactly are the differences? A friend of mine has a 240SX and he's searching for a turbo kit to put on it once his brother finishes the bodywork on it. I'm helping him look for a decent deal and a good turbo kit.. but I don't know much about Nissan engines.

It's a 89' or 90', not sure. Pretty sure it's a fastback bodystyle.

the s13 is from 89-93 which had sohc motors in 89-90 and dohc from 91-93.. came in fastback (hatch) or coupe
the s14 is from 95-98, all with sohc..