This is the set up that am thinking for my 08 a4 (non bose/ non navi):

JL Audio XB-PCS2-2 (amp install kit)
JL Audio G1700 (amp)
JL Audio TR050-CT (tweeters)
JL Audio 8W7-3 (sub)
JL Audio TR525-CXi (speakers) (x2, front and back)
Stinger SHW514BC-1 (speaker cable)

Am open to any productive suggestions and/or comments. For a setup like this, do I need a capacitor, or a higher grade battery? Also, if anyone knows where i can get a quality install (for a good price of-course) in Long Island, NY or Queens, NY. Thanks alot guys/gals.