KD, naw, you're waaay overthinking this. The harmonics that the rubber is trying to dampen is strictly from the engines' internals making noise. That noise is transported throughout the engine, and since the cylinder they are contained in has cooling fins on the outside, it basically acts as a speaker does. However, these harmonics are not powerful enough to be destructive, they simply attenuate the air surrounding the fins and cause what some people hear as irritating valve noise. This engine doesn't run at high enough rpms to cause anything close to that. If you're that concerned about it, leave 'em on. I pulled them because I'm A: not concerned with valve noise, I'd much rather be able to hear it so I can tell if there is a problem with the valve train,B: they look like shit, and C: I've always considered them a hinderance to maximum cooling.