Personally I would recommend not buying the Pioneer in your first post, I recently bought one and I find the sound very tinny compared to the Technics class H it replaced, also the dolby decoder is very slow and sound lag can be a problem.
There has been a lot of talk about them being sold for scrap metal would love to get my greedy little fingers on one of those babies, the things I could build...
you could possibly use outgauge speedo to control 12v car radiator fans (increase in car speed increase fan speed), wouldn't have a clue how to wire or program it but in theory it could work.
try cleaning the lens of the cd player, a rubber mount at the back would only work if the front was isolated from vibration also. from memory that pressed tag in the dash is for the factory stereo to locate with a pin.
it could be incorrect wiring, 12v supply to amp could be mixed with 12v supply to electric antenna, so when AF is off, power to antenna is cut to tell it to retract hence power to amp stopping.
Of all the posts in this forum, I truly believe this is the best most entertaining post ever, true music does not require electronics, mozart, bethoveen, cobain, gifted players, talented musicians.