A couple weeks ago I installed a Lethal O/R xpipe. I have a slight tick/hiss at idle...and notice it all the way up through the RPM range.

I'm thinking it might be where the rear clamps are, where the X meets the over axle pipes. However, I checked again and I have the two pipes pushed right together and the clamps on super tight.

Any install help? Almost at the point where I'm going to take it to a mechanic with a lift and have them find the leak...

 

could be one pipe is a little smaller than the other. Take it off or slide the clamp out of the way and measure the pipes. If you find one is smaller than the other, go to autozone and get thier pipe expander. Make the smaller one a little larger and put it back together.
I had the same problem and this is how I fixed it. Clamps should be tq to 40ft pounds if I remember correctly.

 

I'll check that.

Did you reuse the stock shim that goes between the manifold and xpipe?

 

The best thing to do is get the car up on ramps or jackstands and let it run. You will find where it is leaking. With my X-Pipe, loosening the clamps just a bit was all that was needed to stop it from the annoying, and minimal leak.

Mike