Okay, Here's my planned Audio setup for the SC...
 

Didn't need a DVD/Navigation system so that rule out a double din unit. What I do need is Bluetooth/Ipod connectivity. Anywere I need to go that requires a navigation I would drive the GS or GX. Plus I have a portable GPS unit. So here is my planned setup.

Pioneer DEH-P7900BT
with IR steering wheel control and Ipod connector
2 sets of Polk Audio db6501 component 6 1/2
Eclipse EA4100 RMS Power (4 ohms): 75 watts x 4 channels
Read good things about the amp
Memphis 10" (enclosed) w Memphis Amp in trunk or have the M. Amp push a 8" Free air in the deck if there is a enough room.

I have the prefab, door adapters to the 6 1/2, only problem is the radio installation kit, which have read on here that no one makes so I will have to fabricate something. I heard that the old 92 ES one may work with some modifications. Hopefully the weather will get warm enought to do the work myself. Comments?

i would stay away from free air subs they suck haha. i have a kicker free air in mine pushin 175 watt rms. i swear sometimes i bump that thing sound like its about to break lmaoooo. i think its best to have a sub enclose clean and loud :]

same..ive heard both, and i prefer the sub enclosed as well. and about the radio installation kit...yea, you will have to fabricate your own. that would be the deal if you took it in to any audio installation place. they would have to fabricate their own. kind of a good and bad thing..good because you can fabricate your own kit and make it look exactly the way you want..bad because its not direct plug and play.

good luck! and cant wait to see what it all looks like!

wouldn't go for the polk speakers I have a set of these up front and they are marginal good. There are many others available that are better.

Properly implemented infinite baffle installations will provide you with some of the cleanest bass around. I posted some info about a year ago - link.

I've modeled some Kicker subs in IB installs. It takes less than 50 watts at 30hz to push them beyond their mechanical limits. You may want to look at getting a driver with more linear excursion.

-Robert

i think im just going to pull out the free air sub and just get a 2 jl 12w3v2 put back into my ls400. In a sealed boxed pushed by 2 rockford fosgate p325 amp at 2ohms. i was looking at image dynamics for their IB subs. but i dont think its worth it.