I went with a replacement Walker downpipe,which is NOT mandrel bent,but was more open than the twice dented factory pipe.
I have know idea if a pipe is available from the dealer or if the dent is missing in a dealer item.
Mine goes to a Walker direct fit cat and a Dynomax cat back system(which is also a Walker part).
I have no rattles or leaks,but it does hang lower under the motor...
Its also on an APN header....
I have an uninstalled APN (actually an API w/ same part number) aftermarket header, for a 98 XJ ...
Currently the 98 XJ Federal exhaust .. does not have an OE cross-over pipe with a dimple (dent), that is installed with a leaky OE exhaust manifold. My fuel economy has fallen from 18-19 mpg (average) to around 14-15 mpg (average)
After finding some old posts from 2005 on another forum. The discussions shows, according the several people and posts, that the dent was put there by the OEM for a purpose i.e. to provide 1 to 2 psi back pressure for the 4.0L engine in order to improve the performance and fuel economy at lower rpms.
One person stated that for the stock OE exhaust a straight down pipe would only improve performance in the 4500+ rpm range.
** I could not find any more information about the front pipe for the XJ other than some aftermarkets may have a dimple while others do not, some may have crushed tubing while others are like the OE, others may be either stainless or aluminized and mandrel bent.
Most cat-back systems should work Ok with any type of exhaust system (OE vs performance)
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_ Other things to note: the original OE exhaust used a 1. the old style cat. conv. with pellets 2. was mandrel bent 3. stainless steel, 4. used a more restrictive OE muffler and was 5. 2.25 inch throughout.
_ At one time Jeep offered an optional performance exhaust .. options included 1. a performance header and/or 2. a catback system (a performance muffler with a 2.5 inch tailpipe) there may have been a different intake however .. I don't remember ever seeing a modified intake for that time period ...
_ in 99-00 other changes were made to the OE exhaust system ... some changes were made to the header and/or intake (larger streamlined intake and modified two part header, etc.) ... I think to offer improved economy and performance (hp) and to meet certain EPA fuel economy and emission standards (sometime after 99 there were a couple of pre-mini-cats for some XJs that were added to meet Calif. emissions.)