thats a great idea too, means 1 amp and everythings done... less wiring to worry about, no power distros and the like.
My set up in the stag is rather big, 2x Alpine MRD-M300 mono amps running the 2 Type S 12" subs, 1 x Alpine MRV-F540 4 Ch running the front splits (Active, 75W into each woofer and tweeter) .. Fronts are Focal polyglass 165's
upgrades are a few more amps, 1 for the 8" Mids that are going in the doors and 2 for the 5" Subs that will be going in the front foot wells