I'm new to installing and picking out whats really good when it comes to subs. I've had installers in my town put systems in and quite frankly I would rather put my own stuff in and pay such a highprice than they want. Any ways Im looking at 2 XTR PRO 12s or 2 P3s. They are going in a 99 silverado regular cab. Would like to hear your opinion or if there are better subs that can fit. Preferably under 6.75 inches deep. Thanks.