Is the diablo worth it on stock?

The Diablo Predator is not a chip it's a programable tuner/flasher. Usually these are not worth it on a stock car unless they are combined with gears. So if you decide on putting gears in your car I highly recommend getting a tuner/flasher but not the Predator I'd go with a SCT with a custom burn and you can get one of those at www.modulardepot.com but that's just my opinion. I hope this helped you with your decision