Damn girl that is definitely gangsta you talking about the 240 with teh sr20det swap, you know yoru shit!
Id totally reccomend doing the 240 with the swap if your budget was 10 grand, but shit, 40 grand??
Now I know an important thign to consider here is to start out slow, y ou know what I'm saying? I mean shit, with a 40 grand budget check out the WRX STi or the new Evo VIII. If you think you can handle those cars as a first car then shit go for it, but if youre planning to start out slow, the 240sx with the sr20det is a great idea. Want some more reliability? Get the Integra! And are you sure you werent talkign about the JDM conversion instead of the s15? LOL. N ow that I think of it go with the Integra with the JDM conversion if you arent down with the OEM headlights.
Seriously...a boosted Integra?? Dead sexy.
Good luck!