599 for 4 tunes? I'm gonna run the 91 performance for the majority of the time... Was interested in an "economy" tune but I guess that isn't an option on the site. Nervous but from what I hear it's fun stuff...

 

Do it. My MPG is up about 2 mpg as long as I drive semi normal, which is very hard to do I either run the 87 or the 91 tune, depending on driving distance.

 

No drivability issues? Big difference power wise?

 

Tons of info in the 2011+ engine section. Livernois is one of the more expensive options but is top notch. There is a recent thread in the 2011 engine section about a new 93v9 (I believe)tune but needs a little more r&d. Should be good when they get it ironed out. I doubt that you would run an econ tune after running a performance tune. Performance tune is way too much fun!