I can't think of anything specific, I checked a catalog just now but nothing stands out. If I can help at all, I'd offer that you should shoot for a 4 channel amp to get it over with in one shot, and also look for one with a small fan installed. I don't think you'd hear the fan, and it might help with any heat issues under the seat.

Do you know how much room you have available?

And if all that was already discussed, sorry - too lazy to inspect the rest of the thread!