I go for parts and clamp stuff together. The cat back connections on my 528e s are nuts and bolts. I use grade 2 5/16 hardware instead of OEM 8mm. The down pipes arent too bad to R+R Put a 6 point socket on one side and a vice grip on t'other. Saa-nap. It is a very nice system. The one on Grand Wagoneer is horrible to work on. U clamps on my Jeep are a PITA , but I often can re-use them.