Bun-Bun

OK so I went test driving last week and came home with a brand new (ok used but it has less then 10k on it) 07 Grand Marquis Ultimate. I love the car... except the audio system and the exaust.

It came with the 6disc changer audiophile system which on the ford site for the 08 model it shows the audiophile system has 8 speakers and a sub... I am pretty sure mine does not have that. I havent gone through the whole car yet but by my guess it is 4 speakers (probably 6x8's?) and has an amp in the trunk. However I can not find any specs on any part of this. I am trying to figure out what I have to start with as I need to sell off and buy new componetns to the stereo that I am bringing over from my 88 Beretta. Also I need to know what parts of the warranty I am voiding by installing my own head unit and speakers.

Second thing is the exaust... My Ultimate only came with single exaust and while it is nice and quite... I want my ole dual rumble back that I had with my 75 LTD Landau (460CI w/ dual exaust and turbo mufflers and cats removed). Again would I be voiding any warranty by installing a aftermarket exaust? what would be good choices for complete aftermarket systems for this car? Or should I just go to my local shop and get custom pipes bent and isntalled to fit? (thats what I had done on my 75)