here it goes
they're all in priority order (just my opinion)

1. angel eyes with waffles/reflector removed with either solaris invisibulbs/stealthbulbs... solaris has is really not that bright so you might be better sticking with stealthbulbs..
2. chrome rings for gauge (do 4.4 already have those? i have a 3.0i so i wouldnt know)
3. rims (ac schnitzer, maya, oem rims, hartge, etc...)
4. sound system (if you have premium w/ dsp, get better subwoofer..standard sound system needs the whole system converted to something else...)
5. aerokit (4.6is oem aerokit, hamann kit, ac schnitzer kit, etc)
6. aftermarket exhaust (eisenmann, ac schnitzer, dinan, remus, etc)
7. intake kit (better vroom!)
8. supercharger (lol i want one but its too pricy)