Since the exhaust system has been chopped and welded so many times I think I will replace the whole thing. been looking at Headers, most have 1.5" tubes going to a 2.5" collector. The muffler shop said that with a 2.5L engine the largest pipe I should go with is 2.25". Will it make a difference with the collector being 2.5" then going to a 2.25" exhaust pipe?