I'm not saying you're wrong but from what I've seen people are low 600whp running low-e, pure800 and meth. Titan is running e98 with a similar setup to mine and they're north of 750whp without nitros. Even if you account for different dynos, the gains look a bit bigger then what you're suggesting.
Why aren't more people wanting full e85 setups? The gains are that much again better going from partial to full ethanol.. not to mention its a pain filing up/ getting the ratio correct at the pump.
Sounds like a good start and future plans.
If you plan on tracking it much you should change out the brake pads/ fluid and upgrade the heat exchanger and aux radiators.
Outside of that, I'd look into some the SPL suspension parts to aid in handling and alignment.
Exactly why I went hi-flow catted DP. I might be sacrificing a few HP but it's worth it for how deep of a note it has.. one of these days I need to try out the straight pipes it came with and see what that sounds like
I think it's a good look especially since you lowered the car. Acting and looking like everyone else is overrated. Do what you like and ignore the haters.
From what I understand, the pure's are pretty robust. I can think of a few people running upward of 30psi reliably. If you plan on going pure eventually then I would just upgrade now and save yourself the headache of dealing with the dealership.