Welcome-
There's a handful of us left in the Memphis area (lots of people have moved away recently.) For the most part we do all the maintenance on our trucks.
CPJONES1231 here on mud used to work at Performance Toyota over on Winchester. He still may, but I think he was leaving the area. I think they do quality work at a fair price. (I said "fair", not "cheap"!)
If you want to do it yourself and need a hand, all you gotta do is mention free beer and people will show up to help.
For the electronic stuff, you might want to try one the car audio places that caters to the Grizzlie's players.