I have back to back tested tti’s and hedmans on a 10.80 standard head style sb and a 9.60 to 9.70 w5 deal, hedmans on both combo’s were worth a solid tenth and 1.5mph on both. Hedmans are far superior if needing to r@r a trans and or take pan off in car or working on the car around them, don’t get me wrong, can do it as well with tti’s, it is just way more work. Hedman ttt imop. For et and ease, only downfall is the hedman does hang down a tad more than the tti’s.