What is the benefit of 1 DIN over 2 DIN?
just size and possibly the display difference. on a 2 din the buttons are a little more spaced out and the display is usually a little larger. if you get the 1 din, they will use a dash kit to fill the opening, which will usually place a storage pocket to fill the extra space. i like the 2din because i don't like the looks of a pocket.
What issues do you think I will have with the amp and sub?
well, first off, the installer should test everything to make sure it is all in working condition. although it may have worked in the past, if it was sitting in your garage, moisture could have affected the amp and the subs as well. if these are being installed the same time the deck is, then itll be no issue as far as install goes.
I may have to get 2 separate smaller boxes for the subs. Or is there another solution to this?
the install shop should have many different boxes that you could get that will fit in your
stang. just ask them. plus if they do box building, they could build you a box as well, but they get pricey. i would stick with a single box so that you dont have 2 rolling around in the trunk.
Also, as I understand it,
the two amps in the back are for the 2 door speakers and the 2 rear speakers. is this correct?
yes. both amps run the lower door speakers. the tweeters are run off the radio. the amp could be shot, but there is a chance the radio is. the installer could connect the new radio to the factory amps and see how it sounds. best bet is to replace everything. but if youre on a budget, i would try to keep the factory amps intact if possible. but if it was me, i would replace all the speakers and pull the amps and run those off the radio or even a 4 channel amp.
I'm also replacing the door speakers with aftermarket ones, not sure which brand though.
Do I need to get a new amp to power the new speakers, or do you think the new Kenwood h/u will be able to power most new speakers?
the factory speakers are paper cones. theyre junk. so good idea on replacing them. this makes it easier if the installers need to bypass the factory amps because the ohm load for each speaker will be good for the deck, but if you keep the tweeters attached, the radio will see a 2 ohm load and that isnt good for most radios. i recommend a 4ch amp to power these speakers.
hope that helps you some!!