RV-4 similarities
I have two friends with Rockets, both carpeted and I have not heard either mention of vibration. I have been in both planes myself. I have an RV-4 with similar construction, and it is a known fact that exhaust exit pulses can present vibration or drumming depending on the exit pipe angle. I have a 4 pipe system that is smoothest with all 4 pipes turned inward a few degrees. I put a layer of 1/8" high density fireproof silicone mat with a .025" stainless sheet bonded on top under my rudder pedals to stop vibration and heat and I have no carpet in mine, simply because I like my heels to slide on the metal.