I have an 05 GP with Infinity Kappa coaxials all around, 90 watts going to each, along with two newer model Rockford P3 12's ported with about 1200 watts, a second battery, HO alternator, touchscreen JVC HU, etc. It sounds great.
The only thing I really want to improve is the soundstage, It's better than stock because of Infinity's tweeters being tilted up, but I really would love that "in your face" sound. I'm torn between putting speakers in the pillars or somehow in the dashboard (no stock speakers there). I figured the dash would have less reflection off of the side windows and would sound more even to both me and a passenger.
Anyone have any ideas? I'm gonna start brainstorming tomorrow once I get out of class since I still need to finish my 4th layer of sound deadening (rattles are so hard to eliminate with louder subwoofers).