Quote Originally Posted by redrumracer
why tilt unless it needs to be tilt for a straighter exhaust flow?
Exactly, one 45 degree angle is alot straighter not to mention less difficult to make then two 90 degree angles. I prefer running it straight out but that depends on the original exhaust and bumper design (side of outlet).

Plus having it at an angle can sometimes allows more ground clearance in the rear, if you're often trailering or towing the car that may be useful...