Just did a full audio system in my 08 DC. Panels are easy, steady firm pressure is the way to do it. Buy the speaker adapters on
ebay. I went with infinity all the way around, 6x9s in the front, 6.5s in the rear. Had to space the window track back which is as easy as getting 2 new M6 bolts from the hardware store (1 for each front door) and about 6 washers to space it back on each side. I originally made adapters out of existing speakers, but decided its best to use the
ebay adapters. Many go with 6.5s up front, but you get much better bass response out of the 6x9s. I installed a 90x4 amp for mids / highs and an 800x1 for 2 10in subs.