but an arduino based TPS intercept would be pretty straightforward as such things go.
splice in engine speed, intercept TPS output. pass through tps unless speed > x and tps < y in which case output min off idle tps.
with any luck all the voltages involved should be allowable range for an el cheapo arduino.
Antihero
Putting AMS garbage, and $500 ebay wheels on a Z is like dressing a Victorias Secret model in a Walmart dress and Payless shoes. You're embarrassing yourself.