So I have a 95 mustang GT and My EEC is throwing code 511 which is a ROM error, and codes 412 Unable to control RPM during High RPM Self-test , 172 Heated oxygen sensor indicates lean condition right side, 126 Heated oxygen sensor indicates lean condition, left side, all of which I believe are due to 511. So now that I am getting ready to replace it do you all think there are any advantages to going back to the A9L. I am currently running a SCT chip in my T4M0. Let me know your opinions and if you have either of these EEC's forsale let me know.