UNLESS you are actually USING that 450 hp a high percentage of the time, it MIGHT not really have much impact on engine lifespan. Yeah, at first blush, that sounds silly, but LOTS of us only use that extra power in extremely short bursts - like pulling heavy loads up steep grades - yeah, it stresses the engine, but in relatively short distances and periods of time - the REST of the time, the engine is still loafing like a stocker...<br><br>I'm not a racer or sled puller, and normally drive quite conservatively - but when towing in the mountains, I don't spare the engine, the Comp is on 5x5, and whatever throttle it takes to stay with, or ahead of traffic. I really don't expect to see much, if any, adverse affect on engine life... Ande there's quite a few of us using the power increases ONLY for RV or similar applications - not racing.<br><br>Now, if you DO use that extra power at every stoplite, and every weekend at the strip - all bets are OFF!