I'm gonna do about the same for my convertible, a couple of subs in the trunk with a fairly high crossover point shold take care of the punch, maybe 120-130Hz, that bass is not directional so it will sound good top up or down. Then I got a dual coil center speaker, don't know if its any good yet, if not I'll make a custom speaker fit there, and I'm gonna try to fit as large speakers as I can in the dash corners, hopefully I can find a pair of Focals that I can fit with minor mods. I also bought the kickpanels with Kenwwod 4" speakers already in them from Year One, but the panels look like crap, and the speakers don't look like hi quality either, probably not gonna use those at all. Got a good 5 Ch poweramp, gonna look for some kind of bluetooth device so I can use my iPhone as the source.