Im going to get a cadillac deville and was wondering if the speakers that come stock are respectable enough not to have to upgrade. I notice some new cadys come with 8-12inch subs. Does this one also? And im planning on putting an amp in. Since right now all i have is an amp and 2 subs im going ahead and instaling that. So my plan is to splice into the right rear door and run wire to my crossover. Then run the crossover to the amp. Would this work. My amp is kinda old and only runs in stereo.and i have 2 subs. So is there any way to take the right rear channel and make it into a mono signal. Or will i need to splice both doors?