17k you can probably find a clean newer LS4 then slam it on some pretty decent wheels. That will probably eat up the majority of your budget, but you could always look at an exhaust to let the v8 breath.

 

you can do a decent bit, but dont htink you'l end up with a fuly vip'd out car.

wheels alone will eat roughly 3grand, then suspension (depends whether you go air or not, but either way for a good drop around 2grand+install AT LEAST) then small stuff like Tint+accessories will nickel and dime you too.