if you're looking for a car already modded, I'd suggest checking out
modifiedcartrader.com or
mautofied.com
both are good places for that sort of car, but be wary for your own sake, dude.
I know what it's like to be looking for a first car. The "be wary" remark was meant in this way.
if you buy such a car, with lots of modifications to the engine and drivetrain, look for insurance rates to go up.
If you buy one with only the aesthetic modifications, but none of the actual engine mods to back up the aesthetics, at least, in my opinion, but by no means the opinion of the world, it seems ridiculous.
like the 3 foot wing that would only work if a stock Honda Civic could make it past 190MPH.
good luck, and happy searching.