1999 Explorer exhaust
I kept running into JBA and BBK headers for the 4.0, but most were listed for only up to 98. I know there are some out there though. Whether or not you went with a new set of headers (which is advisable), I would go up and have 2 1/2" pipe all the way back, and a Flowmaster. Depending on your location, and if you can find someone to do it, I would have all 4 cats taken off and go with 1 hi-flow cat.
I have the pipe come from the headers into a 2-in-2-out hi-flow cat, then to a 2-in-1-out Flowmaster, and out the back. All of mine is 3" though. You can run duals, but using larger pipe, the best way to do it is by leaving off the spare tire. I really didn't want to get stuck without one, so I just went with a single out the back.
Has a very good sound - not loud enough to be obnoxious, but loud enough to turn a head for a glance...





