Bull-X Resonator Delete Pipes for B9/B9.5 Audi RS5 – Perfect Balance of Sound and Value Ordered these from Urotuning, and I have to say, the experience was smooth from start to finish. Shipping was fast, and the pipes arrived well-packaged with everything needed for installation. Install was straightforward—no major hassles, just a quick cut with a sawz-all and essentially it’s a simple bolt-on job. Once on, the difference in sound was immediately noticeable. The deep, throaty growl is exactly what I was looking for—adds character without being obnoxious or droning at highway speeds. It wakes up the RS5’s 2.9T nicely while keeping things refined. For a fraction of the cost of a full catback, this is an absolute no-brainer. If you want better sound without breaking the bank, the Bull-X resonator delete is a solid choice.