I drove both, and the PP EB felt a bit stiffer, but nothing major to be honest. As far as brakes... Not a huge difference either. Honestly, I think the biggest SOTP thing was the gear ratio.You'll notice a difference in the suspension and a big difference in the brakes.
It may be specific to that car. The experience was odd, as my expectations were higher coming from my underpowered daily, but I was glad I drove the second Eco.^ I'm kind of intrigued by this. I really like the brakes on the base (and the PP) as they're the brakes from the previous years GT. There's a bunch of brake feel.
Regarding it not accelerating well, that's strange. My EB premium has 3.31's and my buddy's base EB has 3.15's and they're basically identical acceleration wise. I bet from 3.15 to 3.55 is noticeable, but I know 3.31 to 3.55 isn't...
EB PP doesn't have Torsen diffI noticed brake dive on non PP cars that isn't there on the PP car. I also prefer Torsen diffs.