I am definitely stuck in the middle under the new rules. I have no power accessories on the car, and the car gets hard to drive as I add weight. Running skinny tires to make it work (as I did last year) gets harder as the car gets heavier as well. No go on a 3,300lb + porker with manual brakes for me. I would also be running up over the ballast limit. Giving up aero only nets me about 12 HP, and certainly is not the fast way around. I could probably make it work with a serious restrictor plate, but that takes some fun out of the whole effort to swap the V8 in to begin with. Also, my intake setup makes it a huge PIA to change a restrictor plate (can't get at the bolts w/o taking of the intake manifold), so I'd also likely to swap to and e-throttle to make it work.
To make real ST2 power would require a cam swap and a retune, but in the end is essentially a wash for me cost wise, and I'd end up with a car that is much easier to drive (lighter). It also pains me to spend money to go slower
So I'm leaning towards ST2. If I'm under a little on power it looks like next year would fix that.
Ray, the aero penalty in ST3 is so minimal as to almost be a moot point. I'd love it if it were different (1 point plus), but that's not how it is. Once others start inevitably running aero, you won't be able to compete.