2.5\" exhaust pipe to manifold adaptors My old 2.25" mufflers are rotted out and I found a good deal on a set of 2.5" 40-series Flows. The local muffler shop says they probably can't attach 2.5" pipes directly to the factory manifolds. I seem to remember some discussion about a person making adaptors to allow this, but did a search and can't find it. Anybody have any information on this? What about Hummer headers? Are they a diret bolt-on .......or worth it?