I have an 02 Viper w/ SLP pipes, 8DN20's with a total weight of 53.8gr.(4.5gr w/ couple of washers). I got a hold of these just in time for my last ride of the season this past year. It pulls hard out of the hole,(beat an F7 that supposedly had alot of clutch work, in duking 600'and I outweighed that driver a good 50#s) but I believe/know I have too much weight for the current spring which is a YWY primary, with a Hauck G helix, which I believe to be a 49/41 helix. Only revs to like 8200/8300 rpms, but it was also warm/slushy out when I tried this setup on on my last day of riding(March 28th in upstate NY). It was about 40 degree out. I would like to get it around 8800rpms. I was looking for a good aggressive trail riding setup, but for the occassional 600' run w/ the buddies. My sled has a Hartmann 136" kit, w/ 8 tooth drivers. I just picked up a 54/44 B Hauck Helix, which I think shall make it interesting to play with this year, after I take some weight out of the 8DN20's. Hope this helps.
Rick