i dont have access to logging equiptment but thinking of investing in ultrgauge, i had a problem last year with a revision g not hold at wof from 3rd gear on, could hear the whistle past 4000 rpm, it was purely experimental, and tryed numerous different springs and landed on one that was around 20% thicker, that stopped the whistle and car pulled harder from 4000 rpm, it ws rtech that gave me the idea but i dont think they ever put it into production but i could be wrong, im not sure if i had a faulty g or if just wasnt holding all the boost at stage 2 level, but it definately worked for me, seemed similar to the uprated bypass valve for the old cooper s, shut quicker and must have been sealing better from my test.