and JWT runs really rich. so the choice is this... run a little leaner with the ashspec or run rich and later down the road get your car tuned to get the AF ratio how you would like with the JWT ecu. I went with the JWT because its been around ALOT longer then the ashspec and its a proven good quality ecu. the ashspec i herd is a very good ecu as well and still retains "saftey boost" when your ecu throws some codes. Call JWT and ask them about there ECU and then call Z1 and talk to them about ash's ecu. also if you use the search funtion you will see my post about the same question about when i was doing my ecu upgrade. i hope this helped ya