Have used the 24gr for over 50,000 miles - very smooth - which is nice - but actual acceleration improvement (over OEM rollers as tested against a buddy of mine who has same model/mileage as me) is not that much - however, it feels like a lot. When pulling out at a full stop - no one has ever beaten me off the line - frankly, not many have tried/cared - except once and it was a tie. One word of caution, IMHO, is to let the clutch engage (so there is very little slipping during acceleration) BEFORE twisting the throttle wide open from a stop. I used to open the throttle wide from a full stop and hold it open the entire time until I reached my desired speed - this seemed to cause noise (sounded like scraping) in the final drive that would take a long time (weeks) to go away (I would take the drive apart and sand down drum and clutch shoes but this did not elliminate the noise) - I think it was due to bitty clutch shoes trying to transfer more power than they were designed to do over a very short time interval. Now, when I want a quick start (say from a stoplight), I rev engine to get the idle up a bit just before taking off to get the clutch starting to engage - then hit throttle hard - it gets me off the line quick enough and now I rarely get any funny final drive noise. If you can tolerate a slightly slower quick start - wait to the clutch engages BEFORE you open the throttle wide. I have had two SWings - and have noticed the same issue on both of them. I now NEVER do the clutch shoe burn (i.e., holding the throttle open with brakes on while stopped) as it seemed to create final drive noise that would last a long time - instead, I do sand down the drum and the clutch shoes to remove shine each belt change or whenever I have the final drive apart - this has kept my final drive happy (nearly noise free) for the last 40,000 miles. It only takes a fraction of a second to get the clutch to engage with the drum - especially if you keep the rpms up a bit when you are ready to start moving. The SWing is not designed to be fast off the line but I always get a big jump on traffic from a full stop whenever I want too - so it is plenty fast off the line for me.