because the UDP is solid and does not have a rubber shock impact ring like the stock...its being suggested that the harmonics at 2500-3000 cause bearing wear. then again so does launching at 5500rpm. i will say this. the udp will NEVER blow up an engine in a single heartbeat. it may cause 'some' more damage, however, a engine that is ran hard will still have 'some' damage. next thing ppl are going to say you shouldnt get aftermarket turbos because they blow up your engine. go figure?