Take one pipe and reducer to a friendly muffler shop, and have it cut and expanded slightly so it slips over the reducer cone. Return to the car, re-install the head pipe and collector and verify it fits. Now, mark exactly where the head pipe overlaps the reducerthe distance overlapped and its rotational position. Take it back to the muffler shop and have the head pipe welded to the reducer. Reinstall the head pipe/ reducer assembly on the car, and repeat the process on the other side. This makes for lots of trips to the muffler shop, but its a foolproof way to ensure everything fits perfectly. Really! Doing everything at once increases the risk of cutting one or both of the head pipes too short (like we did the first time). Take your time on this step.