i run a custom ava one and make peak power at 6k and only drop 10bhp by 6500(i have other restrictions stoppin me makin it higher) but its not just the peak power ive gained its all thru the rev range,that was comparing to my 195@wheels run on the piper t2.
andy r ran one too on his mega cvh build and was makin peak power at 7200rpm sure he had an 8k rev limit or there abouts
he's runnin 2 customs ones now in his zt i believe