I did the ulmer air box mod with a hauck fuel accelerator. I got the hauck for cheap so I thought I try. I was racing 2004 xc 700 clutching and exhaust mods. That machine works well surprisingly. Anyway, no mod, one or two lengths in 1000" with the mod, same day, same trail I was waving bye bye to the 700 in the mid range. He was pissed. Probably 5-7 lengths. I haven't dialed in the fuel yet. Using aem gauge. It looks like 2 green 2 yellow 3 or 2 red. It really doesn't need much fuel. I think the hauck goes to 8 and I'm using 2 or 3. Anything else fuel is below 12.5. I THINK I'm looking for 12.8 air fuel but no one wants to share yet. Anyone??????? No guessers here just people that have actually done it lol thanks. Anyway air box works, no doubt, period.