With the race kit I run around 16.5 pounds of boost and I promise you that 16 on the race kit is much more than 16 on the non-race kit I had on it before. Not all boosts are created equal.
Paul told me I would be good to go around 19-20 pounds of boost with good fuel and that is more than enough for now. It all about usable power for me, and to be honest more than 20 would delve into the unusable power realm. I don't remember who said it, maybe Tyler Earl on MMM7, but he was talking about what it would take to climb Monster that day and he said something like "17 is all you need to climb Monster". I do plan on building the engine at the end of the season however. If it was a money issue, I would much rather spend the dough on the skid/tunnel/track than building the engine. Leads me back to the usable power issue. If you can't control and maintain it, no use building that much power IMO. Good question though!
Laters!