You might want to check out the "technical discussions" forum, as I had the same question about my changer.
I think I'm going to put in a 2-way switch so I can toggle inputs between the Empeg and my changer, and keep my existing tuner.
As for installation sites, I'd recommend any high-end car audio store (NOT Best Buy).
Jason

_~= Dearing =~_
"WAY too happy about being #1225."
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_~= Dearing =~_
Gettin' back into it thanks to slimrio!