no fitment issues for installing, i recommend working your way from the back forward
no prob over the axel
it touches my spare (which i dont have in right now), but i modified how i installed it a litte, put it up higher
and it rattles up against my tow hitch
i wanna do a cat but for some reason mine has 3! one on each of the pipes before the y-pipe and one big one after

 

fits in really good around the spare. i welded it all together. just because i had access to a welder and then i just welded the tips to the hitch under the bumper. i know it will probably rust out sooner, but it doesnt rattle. so im not real concerned.

 

oh and if you want some noise get a K&N setup sounds like a exhaust system from the front end, sounds awesome

 

yea i wish i had a welder to weld mine up
ive got one but its a mig that doesn't use gas so it throws a ton of slag
i wanna get a gas welder so i can reroute my exhaust out infront of the back tire

 

what k&n kit will fit the 3.9L V6?

 

i think the one for the 5.9 will fit cause its got the same intake style
http://www.knfilters.com/search/prod...Prod=57-1517-2
i would prolly wait for someone with a 5.9 or 3.9 to confirm this