I ran QA-1 singles for nearly 2 years. It now has Afco doubles. So far I've been able to pick-up .03 in 60 ft. It does seem to be more consistent. Though I ran a slew of mid 1.30 60 ft with the QA-1's. I've moved ladder bars,swapped shocks, adjusted shocks, swapped tires. All this has gained me less than .10 in 60 ft.
Doug