I could just review the Bully Dog GT in just one word, WOW! It is amazing how much power is hidden by the manufacturer. The moment I loaded it into my 2011 Nissan Titan SV, I could feel the increased gains.I bought this for twor reasons. First, was to add more horsepower and tourque to my Titan in order to tow my travel trailer. Not that I had a problem. However, if there is more power to be had, why not. I have yet to tow with the Bully yet. And with the season over, it will be some months until I can test it out while towing.The second was to assist with fuel economy. The Titans are known as gas guzzlers. Though I like the look of the truck, what I do not like is getting 12mpg around town and 8mpg while towing. I have only had this product a couple of days, and already I see a difference with my fuel economy. I only assume it will get even better in time.If you tow, or need better fuel economy, get this product. I should add 2 items. I choose 2 day shipping from Amazon. I received the Bully on less than 24 hours. Second, as I am not computer savvy, I called Bully Dog's Tech while trying to update the tuner. The tech was more than happy to help. She was able to take over my computer and update it for my. All the while showing me waht to do. Great product, great customer service.Updated 11/25/12:I just wanted to add that I wired the Bully Dog up to a Switched ACC Fuse for a more permanent installment. I used a Mini Fuse Tap, which is availible on Amazon. Make sure you know which fuse tape you need for your fuse panel. There are two different sizes. With the aid of the Mini Fuse Tap, I was able to complete the installation in my 2011 Nissan Titan in under 20 minutes in the parking lot of a Pep Boys! You will also need some zip ties for wire placement. So I guess this update turned into a testimonial for the Mini Fuse Tap.Update 12/12/2012;I had to tow my travel trailer (7800 lbs.) upstate NY the other day which gave me a chance to test out the Bully Dog while towing. I could feel the difference from the stock settings.Towing through the Adirondaks can be challenging at times. This is a route I have traveled while towing hundreds of times. On the very long steep hills, I would need to downshift into a lower gear to make the hill. Not this time. I stayed in one gear and still had enough power to pass a vehicle if need be while using the Bully. I am impressed.I am running the performance/premium tune now. I could feel the difference between the regular tune. More HP and more tourque with this tune. And I am getting better fuel mileage as well. Without towing I am getting over 16mpg on the highway. Big difference from 12-13mpg. And I am now getting 8.5-9.5mpg while towing from 7.5-8mpg. I also have an Airaid Intake, which also helps in gains and mpg. Needless to say, I am very happy with this product.If you tow, if you want to save on gas, if you are a modification junkie, I am all of the above, you need to buy this product. You cannot go wrong. It pays for itself. Provided you do not have a heavey foot!Note: The Bully Dog GT is vehicle specific. Meaning it may have different options for each vehicle. For instance, with my Titan, I cannot re-calibrate for larger tires. Though I can remove the Wide Open Throttle Restriction on my Titan where other vehicles cannot. You should check to make sure the Bully Dog GT can accomplish your reasons for purchasing it. Check the Bully Dog Website for fitment and vehicle characteristics.

Installed this on my PERFECTLY RUNNING WELL MAINTAINED 2001 Silverado 2500hd 6.0L 137 000 miles. Tuned the truck for towing and changed the tire size setting to the new KO2's I put on. My first trip after the new tune was not good. Truck had a random low RPM studder but seemed to have better overall better performance. Next, the tire setting, inputted correctly, was off by 6MPH after tuning. Got back from the trip and truck seemed fine when I shut it off. Next morning It would not start. With the key off/pulled out, Bully dog hooked to ignition fuse power/ switch set to external power, plugged into the OBD2 Port, it had some type of internal failure, flashing screen and the truck mileage odometer was lit and flashing. I unplugged it from the OBD2 port and lights on the cluster turned off, keys still not in the truck at this point. The Bully Dog seemed to have shorted itself because everytime I plugged it back in, the cluster lit up, odometer lit, Note; it was powered correctly to fuse panel. The truck would not start. HUNDREDS of dollars later and reflashed to stock I finally got the truck running. It totally screwed up the electronic timing, air and fuel settings. I had to test signaling from every sensor, MAF, MAP, crank, cam, temp, air fuel valve, TPS, and fuel pressure regulator, injectors and fuel pump. It had screwed up the tune on the ECM so bad the signaling from multiple sensor were not being precessed properIy. Because of this it even changed the transmission shift pattern to a harsh neck snapping shift. I would never plug one of these units into my OBD2 port. Legal action should be taken against this company. DO NOT BUY.

2007 Avalanche LTZ - Trying to get the updates loaded via USB is a pain, once loaded, install is fairly easy (don't bother reading the directions, they are little help, just follow the on screen directions). Unit is small (which is nice), windshield mount is good but bounces around (I will eventually buy the pillar mount), make sure when you open the package to look for a tiny envelope that has the microSD card for the unit in it! Unit also DOES REQUIRE A 12V switched/keyed power! I ended up using a pin in an unused plug, in the distribution box just left of the brake peddle; so I didn't have to run any wires thru the firewall. NOTE: Most GM trucks 2002 and newer do not have switched/keyed fuses, so finding 12v power that switched is difficult but I found info searching online that lead to the plug I used for my truck.As for performance... It's been installed for 2 weeks, set to "Performance" on engine and trans, very noticeable difference in power, throttle response and shift points. I was hoping I would be one of the 6-8MPG people, but it looks like 2-3MPG gains are more likely. Installed, drove for a week and maintained my 15-16MPG even though I was playing more and doing the preference tests (1/4mile runs). Left for vacation, long 1100 mile highway trip thru the mountains, got 18.4MPG there, 14.6MPG driving thru the Smoky Mountain National Park and touring gatlinburg and pigeon forge (AC running full blast), 17.7MPG on the way home (including several delays for construction where we moved half a mile over 40minutes, AC on high). Overall if I can pickup 2MPG, 60miles per tank, that should pay for the unit in 6months and the drive is so much more fun now! Using the unit for extra gauges is nice, I currently watch the MPH, Intake Temp, Trans Temp and Coolant Temps. Overall nice package for a stock vehicle... if you have a lot of upgraded parts like trans, intake, exhaust, gearing that is not factory a custom tune would be much better and tailored for the actual setup. This unit allows for general factory upgraded settings for a stock vehicle.

Software updates only work running windows Explore. Web site not up to date , no downloads to be had. Over 10ths old, no longer supported. Bad experience.

I was very happy with this product, I use it on my 2012 dodge 1500, can turn off a lot of annoying settings, and saves money on fuel