Title reference: https://en.wikipedia.org/wiki/Dr._Strangelove If you have Spec-U longtubes and the (currently discontinued) Spec-U exhaust. There is a reasonably good chance you know what this thread is about. That hissing/buzzing/resonating/rasping/whatever sound that happens just above 2000 RPMs at moderate engine load. Here's a way to fix that. Credit to XRunnerKid for trying this out first. I'm just here to provide some pictures and part numbers. I am 100% sure your warranty with URD (if there even is one) is void if you do this. I chose this over continuing to live with the noise or putting my stock system back on and waiting for URD to come up with a solution. What you will need: Vibrant P/N 1790 Resonators (2) The updated passenger side collector pipe from Gadget. (Unsure if he's still sending these out): You need the updated collector pipe because the resonators will not fit between the bends in the original pipe. You could conceivably cut out the slip joint between the collector pipe and the Y pipe, or find a shorter resonator. That is beyond the scope of this post however. My shop workbench is full of other projects, so my workbench for this project was the flatbed of my rock crawler with an old traffic sign. Yours may be a more ideal workspace. First mark out all your dimensions. The outer verticals are the alignment marks for the edges of the resonator (12") the inners are our cut lines (10") giving us 1" of insertion depth. Since this pipe has multiple bends, we also draw a centerline to keep proper alignment. I measured 5" back from the rear O2 bung. The resonator will clear the rear bend this way. Also need a centerline on our resonator. Cut on the INSIDE (10") lines with a cutoff wheels or sawzall. We are left with these. Assemble and tack weld the pieces. Remember to align the centerlines. Not the small relief cut I made in the resonator. The pipe was slightly out of round from the mandrel bender and wouldn't slide into the resonator on its own. Even though we measured and marked, it's always a good idea to test fit before we finish weld. If your pipe had any fitment issues originally (the bends on mine were slightly off) you can correct them as well. Finish weld and reinstall. (Let's pretend this is a pretty weld, OK?) The driver side is the same process, but since there is only one bend you can skip drawing centerlines. During reassembly, I found it easiest to install the passenger side first, then the driver side. It's a little tight on the passenger side due to the extra diameter of the resonator. Enjoy your reduced cab noise and lower blood pressure levels.