Mod friendly dealership in Houston

[Caution]

Well I am looking for a mod friendly dealership. I currently have ADM race cold air and Kooks headers and exhaust and of course a conservative tune.

I need to take it in for a few minor issues, radio acting up, drivers side ambient light has a bad spot, and a rear end vibration that comes in at 82 mph. As the mph's go up it seems to get worse. At 95 mph I slipped it into neutral and it seemed to all but subside at 82 mph. I also noticed what seemed to me to be more than the usual amount of driveline noise.
It sure feels like a driveshaft out of balance issue and a loosely setup 3rd member

The radio problem and light problem are relatively recent but the vibration has seemed to get worse as it was always there but now more pronounced as the miles start to mount.

I have had all the tires balanced and still have about 25% of tread left with 23,000 on the clock.

I just don't want to have a bunch of drama about mods that don't have anything to do with what its at the dealership for in the first place.