You feel it and heard it. A slight rumble noise at low RPM, nothing intrusive. as far as the vibe, after it's been in a while you only notice it at start up and when in reverse. Again, nothing intrusive, very mild. I have mine out now to get the RMM update done and boy do I miss it. The CP-E RMM all but eliminates wheel hop. I forgot how bad it was. Greatly improves the power to the wheels. Probably why my Dyno numbers were so strong.After doing my research this will be the RMM I go with. The only thing people keep mentioning is the vibrations go up. How bad is it really? Does it produce like a noisy vibration or is it something you just feel?