Unless your car is brand new or garage kept, your stock sleeve/band clamp is probably in bad shape. The OEM clamp can be re-used many times, but the hardware tends to fail upon first removal. In worst case scenarios rust is the only thing sealing your stock clamp!
Be prepared & avoid leaks by replacing your stock sleeve clamp on install day. Why bother with leaks & rust?
This sleeve clamp is sized to fit 2.50" OD tubing. It is made from stainless steel & uses grade 10.8P metric hardware. It is generally used to clamp our 2.5" exhaust components to 2.5" cat-backs. It also fits a few VW/Audi stock exhaust reductions. It fits all 42 products with a 2.5" adapter. For example:
Mk3 Vr6 Test Pipes 2.5" Through (all fitments)
Mk4 1.8T K03/K04 Downpipes w/ 2.5" adapter
Audi TT 180 FWD & Quattro Downpipes w/ 2.5" adapter
Mk5 FSI/TSI Downpipes w/ 2.5" adapter
Although this adapter is labeled 2.5", it does have the range to fit 2.55" piping. We've been using it successfully on 2.55" connections for years. This clamp comes with our Mk5 GTI resonator delete pipes & also fits:
Audi TT 225 Downpipes w/ stock adapter