From my own personal experience, I had t-6's to begin with and they didnt rev at all and the top end sucked. Then I went to T-5's, they rev'd hard and the top was awesome then it just seemed like it flattened off with the power. Then I had CPI's, I hated not having much bottom end. Theeeeeeen I tried the LRD's. The LRD's pulled hard all the way through and where the t-5's flattened off, the LRD's climbed a little higher. I have mine adjusted all the way in and thats for top end power. My friend has a set on a 421 cub and loves em. He can drag race and then ride the trails. I love being able to adjust them to what you want. 1" adjustment is typical for both max bottom and top end power. A lot of ppl dont know much about em cuz they were a small company. I spoke with Arlen several times (original maker of the LRD's) and he said the same thing. I traded my t-5's for a set of LRD's (the ones I have for sale) actually.