I had the Brenspeed tune for about 15 months. I had no issues with it and drivability was great, overall they are awesome to work with. Back in October I took my car to AED and had it dyno tuned by Shaun for 91 octane and then I swapped over to E85 and he tuned for that. I have a few threads on the forum about the E85 swap and what an incredible difference it makes. With how I have it set up, I can switch back and forth from 91 octane and E85 and vice versa in about 15 minutes although once I experienced E85 there is not much reason for me to go back to 91 octane. I picked up 70-80hp just swapping to E85 and my car put down 688rwhp with no additional power mods and 610rwhp on 91 octane.
2013 Roush Stage 3 M6 Roush CAI, 82mm pulley, ID1000's, KB BAP, Vossen CV3 20x9-20x10.5, Michelin Pilot SS, Lethal O/R X, GT500 axleback, Barton Shifter with 2-post bracket, Clutch Line Upgrade, Boss Trans Cooler, Dynotech Aluminum Driveshaft, BMR Driveshaft Loop, Whiteline Trans Bushing, BMR LCA's with Relo Brackets, Adjustable Panhard Bar, GT500 STB, Steeda X-Brace, Steeda rear sway, JLT Oil Separator, GT500 Diff Cover, Afco Heat Exchanger, 170* T-stat, Tint, RP Fluids, aeroforce interceptors///688rwhp 605lb/ft torque cornfed