S13s are nice car dead cheap for what you get, but not a patch on a S14a (S14s aew nice, just when you sit them next to the S14a they look too plain), id have a S14a over a Saff anyday, and i really like saffs.

Ive driven lots of S13s and S14s, esp modded S14a's as lots of mates have em.

Best value for money car there is in that price range.

S14a is the one to get IMO, Fast, and with some basic mods, VERY fast, spot on brakes, and fookin awesome handling (All SXs seem to handle amazing, but from my experience S14a's turn you into a RWD driving god from nothing, serious, you can hang em sideways like an idiot far better than any other car ive driven before, and a mate of mine went from a shinky Primera straight to one and was broadside everywhere with ease straight away )
S14a's look quality too, try n get the touring with black leather n nicer side skirts too, pretty common, evil headlights n spot on bodykit as std, jus change the wank std rims n get rid of any orange bits of indicators (if its a black one, best colour, just get the tint spray out, job done) and they look mint. 19s go on with no arch mods too if u fancy it.
Main thing is FULL turbo back zorst and a decent front mount intercooler and its a LOT faster and freer revving, as both the std items are piss poor. Then cone filter and 1bar boost and you get at least 270bhp (no chip) and belive me, its fast, faster than a stg1 cossie and so much better looking n handling n stopping.

I love em.

S15s are the bollocks but the chances of your getting one is dead slim as they rare as and expensive compared to 13/14.

300ZXs are tho.