I don't know if the 250 ECU will work, since it controls more than just fuel. I ended up just purchasing the racing injector kit (8000H7557), since I was still running the stock TE250 one, along with the original crummy injector before the build. When you're in that deep it didn't seem like to big of a leap. The bike continues to run like a dream and has been to Colorado twice. The PowerCommander and AutoTune work wonders at all the different altitudes we ride at. In fact the only bike in our group that's faster on the jeep trails is my 525 EXC. My son will dust me on single track. The TE is just so flickable. Keep in mind, my build was on a X-Lite engine vs. the 2008 mentioned above. Good luck on your build.