Tacked up a new "downpipe", not sold on the location yet, but I don't have enough elbows to much else at the moment.
I'll probably be foot brake racing next season - 11.5" rotor with dual 4 piston calipers or 13" rotor with single 4 piston caliper?
I hadn't thought about a pinion brake, that would be ideal I would think.
I do plan on running a trans brake at some point after my wallet cools off a bit. Maybe next year.
Everything I can come up with says dual calipers will be necessary. The smaller rotor will allow for a 15" wheel which will increase your tire options.
What's a rough idea on cost
I guess it depends on what you're starting with. I'm going with a 9", so the dual caliper upgrade was a couple hundred more than a single.