WRONG! That's like saying you can only hook one sub to a mono block amplifier... It just isn't right... He could run a 2 channel amp to those of he wanted to.
I'd go with fuse and buy a lot of extras, put your fuse where it's easily accessible... I have no idea if it's good or bad, but I've not seen anyone use a circuit breaker on this thread, but I have at a car show.
TBH I think you're an idiot to buy a new car.... much less plan to throw a system in it, that means totally taking lots of shit out then putting it back together, it's just a bad idea in my opinion that is.
I hear so many people say "I hate ported box's" and I also know so many of those have never heard a custom ported box, other than when they drilled a hole in there sealed box.
Only time it doesn't work for me is when it's hot.... But if you were to do it and take your time, and clean the surface and plan it out, i think it would work well, i know people use it alot on there floors under the carpet.
What would a gangsta do for an ice cream bar...
The Klondike Bar Remix...
http://www.datpiff.com/Gangsta_Hit_By_Ice_Cream_Truck_klondike_Bar_Remix.v24676.html