If it'* throwing a code with your stock stat, it means that your stock stat is hooped and does need to be changed.
I had not problems with a 180 Intense stat throwing the code.
It was only after I drilled a couple more holes in it.
Then when I went to the 160 stat I had the code disabled.
I don't worry about mileage because I am fuel foolish and care more about the power.