The stock up pipes have a donut gasket that keep them sealed over time they start to leak. The reason there is donuts is to allow movement when the pipes heat up and cool down. Usually replacing just the donuts won't work because the pipe is damaged. So by removing the donuts and adding bellows it will stay sealed up and allow expansion and contraction.
I just installed a set a few weeks back so cannot attest to the longevity. The Holes for the bolts are run all the way thru now so the bottoming out of too long of a bolt should not be a concern at all. Had to do a bit of cleanup on the baby's butt due to some metal still being inside from the machining. $160 shipped to the door from Advanced after digging for a $50 discount code. Boost is up to 27'ish from a max of 14 before.
kinda tough for us guys with "early 99's", motor date code of june98. I dont think anybody made bellowed pipes for that transition model. if anybody knows, please tell me QUICK, as my motor is out but going back in soon.
FYI since your talking about Dorman up pipes I thought I'd put my 2 cents in. I had a leaking driver side exhaust manifold and ordered a Dorman manifold to replace it with. I broke 2 of them before I just returned the last on for my money back. They both broke in the same place, the first bolt closest to the radiator. Torque them to 45ft lbs and "crack" The problem with them is the big "China" cast into them. Save your money.
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