Fronts: "mild competition" obtained from TRF. Since, I have heard that the actual source of those is TSI. They might be a little cheaper direct from him.
Rears: Moss #851-180. Not the prettiest parts I have ever seen, but they have an extra main leaf and ARE stiffer. They were on sale all this last month. Sorry to report that the sale is ended.
I plan to install the Addco 3/4" front sway bar too. They make a rear bar as well, but the consensus seems to be that it's a bad idea.
The TR sidestep: The rear axle is sitting OVER the frame. When the car leans in a curve, the frame rises and picks the inside wheel up off the ground! Often, the car lurches a bit and the wheel drops back down. Also, sometimes, this is the beginning of a full-on spinout. My goal is to minimize body roll. If I wind up with a somewhat stiffer ride, so be it.
As I said, it will be a while before I can report on how this all turns out -- but I will! When I found this place a few months ago, I did some searching through past posts. I believe I read some that are a source of the advice not to use a rear sway bar. There is some previous talk on TR3 suspension back there, if you look for it.