I have done more than a "chip".. I write my own tunes.
I'm not sure where I've posted it.. but do a search on my screen name and you'll find out what I've done.
Summary: Leave fuel alone, run 92+ octane, and jack the timing waaaay up. From the "tune" aspect this is as good as it's gonna get.
Also, never underestimate friction and drag. Make sure tire pressure is good, brakes aren't dragging, nothing in the FEAD is wore out, and your not carrying aound stuff you don't need to.