Thinking about putting a new exhaust on my truck. Seems most of the cat-back, bolt-on systems come in rear and side exit models. The rear exit model seems (from the images I have seen) to have alot less bending and a shorter run length (due primarily to the lack of bending for side exit). Basic physics tell me that the rear exit system should provide less resistance so that system should see somewhat better performance. Does that make sense? Do the rear exit and side exit models differ in thie regard?

How about the more general question - why is one style better than the other? Thanks.

For the wheeler, a side exit would be better. With a rear exit, the departure angle will be less.

An exhaust pipe can get banged around pretty good no matter whether it's side or rear exit, depending on the situation....just make sure you talk to the shop putting it on, and get them to tuck it in as much as they can if you think it will be an issue...
I opted for an angled-rear exit...



It does take a little from my departure angle, but not much more than when it was stock...

Good luck!

My local shop said they could not do dual outlet because the pipe would be to close to a fuel line or brake line or something.

Understand the side exit offering less chance of getting bumped around off-road. As I'm a 98% on-road driver, I care more about the performance of the exhaust - plus I'll be buying one of the cat-back, bolt-on systems and doing it myself. So, as far as performance goes (opening up the engine to enhaust more freely), does the less-bend of the rear exit exhaust really make it make the engine breathe easier?

I opted for straight out the rear...



and so far (knocking on wood) I have had any problems off-roading.My hitch should take most of the scraping anyways...

Mine started out on the side, but every time I go offroad, it migrates more toward the rear. It is slowly bending back.....

Find a new shop...I took mine to Midas and they were able to do it. 'Course it was a buddy of mine, so he was probably a little more willing to go the extra mile...I showed on page 2 of my little web page (link below) how he routed it...check it out if you want...good luck on whatever you decide!

But you've got a trailer hitch, nothing takes more away from the departure angle than a trailer hitch.

BTW, depending on how they do it the rear exhaust won't take away from departure angle.
The big problem is having the exhaust in a place where it won't get pinched shut when it gets wedged between a rock and a body panel/bumper.

In the end it comes down to preference, neither has any bennefits over the other.

I agree...My hitch would hit before the pipes do....

That's one of the bennefits of the hitch, you don't pinch the tailpipe shut.
You just have to get used to it grinding over obstacles all the time. :p

If you put it straight out the back , you'll get lots of exhaust residue on the back. Look at a ricer pickup , the tailgate is usually black by the exhaust .

I've been thinking about cutting a hole in my bumper and going straight through. I've crushed about 6 exhaust tips, both side and rear exit. I was real disappoint to destry the calmini tip. Right now it goes straight back and is just angled down, but inside the bumper. I'm not too fond of it being completely under the truck, but it hasn't killed me yet.

Mines the same way. I've driven for hours and haven't fallen asleep at the wheel, at least not for anthing other than sleep deprivation.

If thats happening I'd be a little more concerned as why it's burning oil...

Besides the offroad benefits, here is a good reason to go with side exit:

http://www.xterraownersclub.com/ubb/ultimatebb.php?ubb=get_topic;f=1;t=007761;p=1

Well that doesn't worry me all that much considering that in majority of cases when someone rear ends you it's the other persons fault and they'll have to pay for it..

We're not talking about high performance engines here! The xterra isn't going to gain any noticeable power increase from one exhaust over the other. Choose the one you think looks the best, then hit the trails.