I own a 2008 G35x sedan. I understand the Bully Dog tuner works well for hp gains. Can this be used on the all wheel drive models? Or only rear wheel drive? Can anyone direct me to a better tuner?

 

I thought the bully dog had no gains for our cars.

 

+1 - according to the dino, my G actually lost a couple HP with the BD. But if you want to try it, it would be the same for an X vs. an S.

 

I still haven't dyno'd mine but I'm not unhappy at all.
Only the machine will tell for sure, but I'd bet a nut that I have gains here. Of course, I also have a few mods on my car and that may have made a difference.

I also got to set my timing +2*, gained a few MPG and I've set my own custom top end and shift points.
There are good things that come from it... it's up to you to decide if it's right for you.

There are better tuners, but plan on spending a bit more by the time they're in and tuned.
Search through the tech threads... there's plenty of information.