iis your 91 octane tune an emailed tune where you put in the upgrades you had? if so that one is better. As far as if it is just the tunes on your tuner than performance will work better. I would assume. That is how SCT is atleast.
ok, ya that should just be better response. That is kind of what I noticed on my tuner. I have the SCT one with the tunes and i have the performance 87 octane tune and it seems to just give better response.