There aren't any independent shops in Dallas, so you'll have to go to a dealer. I've had good luck with Goodson Acura in Irving. I've taken my RL to them since moving here in 1999, and they assisted me with located and purchasing my 91 NSX. They've been great. The only issue I had with them was when I had some tires mounted, but the problem was with the NTB that they contracted the work out to. They resolved the issue immediately. Talk with Susan Tableman - she handles most of the NSX customers, and once you meet her, she'll remember you for life. She's great.
I'll also email you some other info privately.
EDR
91 Black/Ivory #3012