I've heard good things about the MTX 7500 series subs, or their MX something or other line. Someone on here also mentioned ID, can't beat their stuff either. Sounddomain is authorized to sell them on the net, but there goes your whole situation with a shop installing right there, unless you just want to outsource it to one. IMO, if you are unsure about all this, just go around to all your local shops and chat with the guys and have a listen to all the products they offer, then decide. Most places will cut you a deal if purchase everything through them and/or have them install it all. Shops get a bad rep, but they are an extremely useful tool and this business would die without them.