Might not be able to tell that way either, with respect. Traction issues in first and second gear, sometimes in third, can make it very difficult to get reliable, repeatable measure of change in engine power mods. Try WOT pulls in fourth gear from about 55 mph up to 100 mph. Start a stopwatch as the speedo needle hits 60 and stop it when it hits 100. This is very repeatable, very reliable and eliminates all the variables that get introduced when trying to launch a FWD car with little to no traction in the lower two gears. Make several pulls on the stock tune and several with the HT on the same day under the same conditions, being careful to avoid any heat soak issues. This will tell you whether any mod, including HT tune is improving engine performance.