Byam propeller at KFTW. 336 Gulfstream Rd Fort Worth, TX 76106 - (817) 625-0161. They just did mine. Went from 2 ips (yes, 2 ips) to .07. I think the costs is $180.
Mike Ferrer of Roanoke will come to you! No need to fly in to Meacham with all the mess over there right now. Mike is very accurate in all that he does and his rates are very competitive.
He's on this forum but I don't have his email handy. Check past posts in the Search link for transponder checks and you should find previous posts about his services.