I removed the restrictor from my AE .15 and is runs well and is reliable, but it can't compete with engines designed for racing as the .12 CVR, .12 Picco, or .12 NovaRossi. I leaned mine waaaay out one weekend and it was starting to really run great, but the temp went right up to 280 degrees. I know some would run it that hot, but I prefer to keep it under 250 degrees.