Haven't been on in a while - work has been, well, work. It pays for cool rally things but doesn't afford a lot of time for rally things.
Anyway, I've looked into the MCA suspension bits. The exchange rate is very favorable - like the best it's been since the recession. I just bought some new TRED Pro recovery boards on their Kickstarter campaign. Shipping was included so the only thing that will nail me will be duties. I'll let you know how bad those are when they arrive in April... if I remember.
The best reason to go with MCA is that just about every Rally-prepped S-chassis in Oz is running them - at least six, certainly more. MCA has developed a pretty impressive time-attack S13 as well. So, they know exactly what you need. However, for a decent set with mounts and springs and no canisters, you're going to spend just over $4200 shipped plus duties. I just got a quote from Mr. Coote a few months ago as I'm in the market for boingers. Those prices John posted haven't changed much.
A similar set of custom, bolt-in Bilsteins will run you under $4k. However, when you need them serviced, time and postage are going to be very much in favor of keeping them in this hemisphere. Like John said, most people here on the privateer level don't use remote reservoirs. We don't go that fast and our stages aren't that rough. So they're over kill - especially for you right now.
DOHC KA's can be found cheaply also. In fact, I'd highly suggest finding a running DOHC setup to drop in your car. Get the ECU and everything. Then do a high-comp dual cam KA build with the single slammer you've got there on weekends you're not racing. I might know a guy who can hook you up with a decent parts dual cam KA that you could use for that high-comp project. As long as you don't mind taking a road trip to Michigan or paying for freight... I'm sure you could source stuff locally though.
The rears also have some separation issues. I'll dig through some conversations I've had with Dicko Thomas and relay some of the helpful information he shared with me.
Have you tried reaching out to any of the NASA scrutineers?