It seems I have a problem with the tubular exhaust manifolds on my 2000 v6. The sound gets louder as the car runs for a while. I took it my local Mieneke shop and ask if they can remove the manifold and repair it by welding the cracks. They wouldn't do the work as they felt it was fine to drive with that. They did say I could replace, but recommended I only replace with original part. Does anyone have any other suggestion?