Diablosport predator?
 

Can it be used on more than one vehicle? I've read somewhere that someof the tuners can be used on more than one vehicle...

only if you unload it from the first vehicle then reprogram the second vehicle.

Cannot program 2 vehicles at the same time.

Okay, thanks guys. Anyone know of a tuner that WILL support two at the same time?

no handheld will. you can get a program like efi live or hptuners and buy credits for extra vehicles i believe, but they cost $$$ and can be difficult to use for a novice.

...but if you have the time to do it, the money to spend on it and maybe a few friends who want a tune, you can't beat it. Maybe just find a place where they do tunes and tell them what you want. If they have a dyno its even better.

If you go for a hand held tuner get the Predator. I have a bunch of custom tunes saved on it that I have tweaked over the years and I am happy with it. I had someone take off a lot of the torque management and I bumped up my fuel trims and shift parameters. Now I can get most new trucks off the line and my truck isn't highly modified at all. In some cases its ONLY off the line but I am happy with that and 18 MPG.