AHA, the 02 MCS. At 185K KM =~115K Miles.
The runflats are too expensive to track, through something cheap and sporty on your spare 16". I ran 15" on mine, because the tires were cheaper.
So tires are a pretty mandatory. If your shocks are original they have been dead for a long long time. You are going to have to pull the struts to put in the camber plates anyway.
Given that, I would suggest you prioritize like this:
1) Tires before the next track day
2) Shocks/Camber Plates/Any Springs but H-Sports
Single Adjustable Koni/Bilsteins (I ran koni's on mine, but they died unusually fast on all the Atlanta Mini's that ran them, no one knows why). The H-sports from the area all failed also, they just sagged all the way down, once again no one knows why. Camber plates, up to you, there should be some pretty good ones out by now. Get ones with markings, makes it easier to swap settings. All of these things come off together. It just makes sense to replace them together.
3) The front sway bar is impossible to install, so don't
4) The rear sway bar is easy to install, add it after you get those shocks swapped.
5) Check your front and rear control arm bushings. There is some sort of crowbar trick no that cuts replacing the fronts form like 8 hours to about 2. We never did figure out how to do the rears. (by the time we knew they were bad, they car was scrapped)
So the only thing you HAVE to do: Brake Fluid (buy a powerbleeder), and tires. Go have fun, keep it under 8/10th's. At this point you only have four settings to get wrong, tire pressures. I started at 38psi cold, and then bled back to that as they heated up. However, Atlanta is not Canada. Typically advice is to start at the max load rating listed in the drivers manual a figure it out from there. Easiest method: Get a tire temp gauge/probe. Have pit crew tire temp (inner,middle,outer) each tire with pressures as you come out of the session. Add pressure to even temps. Until you get camber plates, its gonna be hotter than hell on the outer part of the tires. Your goal is even temps.
When you start pushing it harder, do the spings/shocks/camber/rear sway. Start soft on all settings and work your way to hard. Keep a small log book of settings and your impression of how they worked. Generally you keep the same settings for the entire weekend. Change them at home, and try them for the next weekend.
Once you have all this, I would step up to r-compounds and start the entire process all over again.
There is a reasonable argument that you could start with a set of HARD r-compounds and go from there. Its your call on that. The Mini LOVES r-comps; however without camber plates your could cord the fronts in a single weekend (or cord 4 on the fronts and 2 on the rears on a single weekend).
Crap: IMPORTANT TIP when you swap out the rear springs, you have to get adjustable lower control arms to correct the camber. I think its just the lowers you have to replace.
Other than that, work on the car at home, concentrate 100% on driving at the track. The most dangerous session you will ever do is the last one on Sunday; so don't be afraid to call it early and go home (Panoz racing school advice). Fatigue and track time are bad m'kay? Get some sort of in car instruction, preferably front wheel drive instructor. Listen, listen, listen, listen, listen. If you don't get along with them, politely get a new instructor. I can name the instructor responsible for every single one of my magical laps, its the dude in the mirror that totaled my car.