Ya huge difference, run the whole slp kit and you will ride with a perma grin! I was one of the first guys to get a kit and I am totally satisfied. I run or beat all the new 8s to this day.
I'm running the 3-6000 domes with 500 mains. I have run pump with no issues however I do like to mix a bit of avgas in as a precaution. I believe I'm running stock needle postion with a 10 thou shim. The setup works well you won't be disapointed.
i run at 6000 plus and i have the 6-8000 domes with 480/490 mains staggered jetting, v force 3 reeds, i got the head with the kit so y pipe can and air intake. i run 91 pump fuel with 2-3oz of lucas octane booster per tank. sled runs awesome. i only mix 40/60 race fuel when i go out sledding with the nitrous bottle filled.