[Fat Charlie]

Miles spent testing is just as legitimate as miles spent doing anything else. Driving myself to somewhere I want to go isn't any better or worse than driving myself because there's something I want to do while driving.

Testing may not "pay off" in that you aren't getting anything "useful" out of that driving and it affects your overall average, but it's data collection. If you want to collect data, the driving is just as useful as any other trip that you want to make. My mods are either too expensive to A-B-A (tire size/type/pressure) or so self evident that testing would be silly (instrumentation/driving style). If I ever build the Aerolegacy (I don't think so!) then I think I'll just point to my logs and credit any gain in that time frame to the mods.