Looks good! I used to do heaps of car modding on photoshop years ago.
I can tell you know your stuff because the rookie mistakes are forgetting to change the background through the cars windows and/or reflections but you even included the skyscraper reflections on the wet ground infront of your car, awesome!
MODS: catback exhaust, RRM SRI, 6000k HID, white led's all round, 22% tint, Rear swaybar, LED drl's, chrome stealth turn signal, scanguage II.
Sound system: 2 x Alpine 6.5" speakers, 2ch Pioneer amp and Fusion 10" subwoofer tube