New turbo, old gas
 

When going boost, you should have higher octane gas to avoid detonation. So what happens if you have a gas tank full of regular (87) after finishing the build or when going to the tuner? Drop the tank, and trash the gas?

I personally would suck out as much of the crap gas as possible before running the engine under boost. Or if you have an internally gated turbo, disconnect the wastegate solenoid and run no boost till the tank is empty. Its just not worth the risk of destroying your motor.

Offer someone free gas if they siphon it themselves.... it will be gone pretty quick.