Installed the Diesel Freaks 2.5" straight back exhaust yesterday. Heard some folks complain about CAT bolt access. I sprayed the bolts with a little WD-40 break free. Then used a 20" socket extension to reach 2 of the bolts. (13mm deep socket) The 3rd bolt on top next to the firewall takes a short socket wrench with a 13 mm deep socket. It is tight but do'able as long as you don't have gorilla arms. The new exhaust flange and turbo bolts didn't see eye to eye. So I put the nut back on the bolt thread, then carefully used the long socket extension as a prybar to nudge the bolt into alignment. This was risky but worked fine for me. The rest of the install was pretty easy. Took about 2 hours start to finish by myself. Sounds great!!!