[Ryan from Ohio]

Any head unit will fit, you just need to MAKE it fit.

There is a plastic "case" which our HUs sit in. Cut it, rip it, break it- just clear the path. Theres also a metal strap back there, I cut mine out.

Ive heard the later Aleros also do not have a switched 12V wire in the stock harness.

Just buy the module. They run about $60 as stated, thats at dealer cost even.