Description:

As long time Pontiac enthusiasts and a G8 GT owner, Overkill Motorsports is proud to extend our reach beyond the V6 world to the G8 GT.

While there are plenty of do-all tuner options or high priced custom options, we're here to offer something affordable with a personal touch. Tuning is available through both Diablosport, EFILive Autocal and HPTuner products. Horsepower gains, driveability improvements, way more features than a typical tune, the high quality level of workmanship you'd expect from an Overkill tune.

Features/Benefits:
  • Dyno tested gains of 16 wheel horsepower on factory setup, 20+ on intake/exhaust setups
  • Tuning customized for each popular intake brand including Rotofab, Spectre, Vararam and fenderwell intake. LS7 MAF tuning also available
  • Torque management smartly revised to eliminate power limitations
  • YOU'LL LOVE AN OVERKILLED TRANSMISSION! Completely revised shift behaviour at part throttle in both normal and performance shifts provide better upshift points and downshifting at part throttle
  • Safety upshifts in Tapshift, auto downshifts as required to reduce transmission stress, auto downshift to 1st at standstill
  • Displacement On Demand in 6th gear highway only, can be disabled on request or manually using handheld
  • Speed limiter removal
  • Reduced Traction Control intervention
  • P0420 removed for high flow cat converters







This option gives you an Intune handheld, plus Overkill custom tune

Tell Us Your Modifications



Overkill tuning is available if you already have an Intune or Trinity device and even if you already have a custom tune from another vendor. Overkill tune files are provided through email which can then be uploaded to your Diablo device and flashed into your G8 GT just like the Diablo preloaded tunes. Purchase price will include revisions for new modifications as needed for as long as you own your G8.

Tell Us Your Modifications




Diablosport Intune: The most user friendly way to provide our Overkill tuning is through a Diablosport Intune handheld. No laptop is needed, no physical installations, no software installations. The Intune can read, scan and flash from inside your vehicle. Overkill tuning is provided through email and purchase here includes retuning for as long as you own your G8 GT. This option is ideal if you want an easy to use option with some controllability through the handheld such as DoD disable and tire size changes.




Select HPT Suite
Tell Us Your Modifications




HP Tuners Suite: Another great way to provide our Overkill tuning is to sell you your own HP Tuners suite. You'll need a laptop to read, scan and flash from inside your vehicle. You can then provide us with your factory file, we provide Overkill tuning, you provide scans and we provide revisions as needed. This option is ideal if you want to do some of your own tinkering but with the option to leave as much of the tuning to us as you want. The purchase of an HPTuner suite here includes Overkill 91/93 tune plus no charge revisions for as long as you own your G8.
Standard vs Pro The tuning suite itself is the same, the difference is the Pro allows for external inputs, such as a wideband input which we will offer in the form of a rental.