H&R SS will definitely drop you lower. May need to consider bumpsteer kit. One of the reasons I chose the Pro-kit is that they were tuned for Vert suspension. I expect that our springs are heavier in back to take into acct the extra couple of hundred pounds. I'm sure that there are folks that are very happy with their H&R SSs on a vert. It would be good to hear from them too.
Bilsteins are great. They are firm but have great dampening in them and are able to isolate to hard bumps to transferring up through your spine. If you have the extra $$$ for them they are great. If you plan to go between autox and the track then you'll want the adjustability of the Tokico's Illumina's. I don't do both, mine is just a mild corner carver setup.
MM C/C is what I have and they are the best!
I went with the urethane bushings in my UCAs, LCAs, spring isolators, and steering rack bushings. They provide a more solid feel while still making for a reasonably comfortable ride.
You're definitely on the right track. When you're all done you're going to be VERY happy with your results. It will be like having a new car (or at least the way the car should have been built in the first place).