If you havent had it done yet, talk to Justin at VMP Tuning in DeBary. Hes got an SCT tuned 2000 V6 Mustang running 10.70s....
Hes pretty well known in the V6 Mustang circles, but tunes everything.

And mofo, the XCal 2 handheld usually IS a custom tune. The handheld is just used to select which tune you want to load, to scan trouble codes, and to do datalogs.