Yeah, you get a lot more boost with premium. I run premium exclusively now, even empty. And I'd definitely use premium when towing ANYTHING, especially in summer. My truck didn't like regular, and boost only climbed to about halfway the gauge. Now it goes about 3/4s. It's a shame FORScan couldn't add numeric number, to know exactly how much, but performance improvement was substantial, and since I use the truck mostly to travel (at high speeds in TX), it's almost a wash to use regular than premium. And now that gas is cheap, I wouldn't hesitate to use premium. Use it for a couple of tanks, and judge if you want to keep using it or not. But for towing, even 2,500, you add a lot of stress to the motor, so don't be a cheap skate .

 

I don't know the programming will actively lower boost to reduce cylinder pressure but it will pull timing and possibly add fuel. This will reduce heat and pressure so the turbo will not spin as fast reducing psi.