I'Ve tried BTA and wouldn't go back I had my bf xr6 t tuned by them(390rwkw) and had problems since day one. Each time I gave the car a little squirt the speedo will drop out, the car will stall and will idle rough, sometimes when it did this my input shaft used to break. Will also struggle to start every morning, went back multiple times left the car there over a week came back and nothing was done, he tried doing a sorts of diagnostics and each time will charge me for it, changed so many parts and issue still hadn't been fixed so just ended up selling the car, bought a fg tuned it with autotech and have had no issues.