Need tcm support!!!

ya i thought it would have some knock issues, im a mechanic at a transmission shop, how much would it cost for a custom tune just curious?

NOTE: The use of respective grade fuel should be used with tune choice.
The 87 octane tune will run fine on 87, 89, 91 and 93 octane. 91 octane tune will run on 87,89 and 91 octane. The 93 octane (Performance) tune will run on 91 and 93 octane.

THis is directly from how to adjust parameters on the ...

one thing i need to know is in iowa we have 87 89 91 oct gas
will the mid grade work on the performance tune cause this is the cheapest of the three then 87 and 91 the most expensive

i have heard mixed reviews on the predator that is work and that it causes less power and less fuel mileage?

I am wondering what benefits you get just using the 87 option verses the 91 or performance and doing custom tuning i read about how to adjust long term fuel trim.