Wanted to do up the Flex wth some Alpine so picked up some Type X speakers, PDX amps and Type R subs. My ultimate goal is just a loud clear system. So far this is what I have installed:
Head Unit: CDE-HD149BT with SAT radio unit running into an Audio control Matrix and Epic150.
Amps: PDX-V9, PDX-M6, KTP-445U
Speakers: Doors, SPX-17MB front and rear. A pillars SPX-137R, Center SPX-107R Mid with 2 tweeters. D pilliars SPS-410.
Subs: Two 8" Type-R in front kicks. One Memphis SHP-15 out back.
Misc: Alumapro CAP15
I made kick panels up front for the 8" subs and custom pods on the a pilliars and for the center channel. Mounted amps in the rear quarter panel where the factory sub was. Box is a PK designs. I have the KTP running my center channel and the set of 4" coax out back. V9 runs doors and a pilliars. M6 is running the 15". Future plans include another PDX-V9 and a PXA-H800. I also have two more sets of 5.25's possibly for the doors.
Sounds loud and clear already only going to get better.