Here's my advice
First, pair up with someone who knows about BMWs and race setups. My suggestion is Phil@Bimmerworld, which has been flawless building out three track cars so far.
I got the 2WNR setup earlier this year. 700/1000 springs (6" and 8"), helper springs up front and GC hardware for the rear perch as well as the race camber plates.
Really happy with the setup. I drive the car to track events and they're always really friggin far (4-10h drives one way), so I cannot have a rock hard suspension especially when using race seats.
The car has a square 10.5" BW TE:AL wheel setup, so with a front 6" spring plus helpers I needed a 12mm spacer to clear the perch properly.
12mm spacer on a 10.5 ET27 wheel is very aggressive. I spoke to BW which recommended switching for a 5" front spring, which I did over this weekend and now I clear with a 3mm spacer! So I'm quite happy.
Of course if you were running a 10" wheel I don't think in either case you'd need a spacer, or maybe just a small one
On track review
This is my brother and I figuring out suspension settings:
It's surprisingly compliant. My students GT3s are sprung so much harder it's not even funny. It's quite easy to dial settings in and modify them to suit different tracks or driver aggressiveness.
With the same tires, we dropped 3.5 seconds on our first outing in a 2:10 track. Not bad!
It is so compliant you can jump curbs and the car lands completely composed.
Road review
I dial them down from the track settings for the drive to/from the track. The car is surprisingly comfortable. It's more compliant than the stock EDC on Sport+ even on track tires which have harder sidewalls than street tires.
The ride is what you'd expect in a sporty car and never makes me feel like my teeth are going to fall out. After driving the 7h drive to Pitt Race I called to BW to make sure that the spring rates are not too soft for optimum performance.
I find track seats are a way bigger hindrance to street use than the suspension, even at 700/1000
It is mind boggling that a suspension with solid camber plates can be this comfortable.
At lower speeds I hear some light clunking which may be the same issue Mobbin mentions, but I was told to expect this.
I also have a JRZ with 500/800 springs with stock seats on the other car and the MCS is more compliant and MUCH quieter.
There is a clear difference between 'tolerating' the ride of a car and being perfectly happy with it. I expected to have to tolerate the drives to/from the track with the MCS suspension, but I was wrong. I wouldn't hesitate to have this suspension with these springs on my street car.
Next steps
I'm going to sell the JRZs and either get the Bilstein Clubsports for the E92 and keep the MCS 2WNR on the E90 or sell the JRZs, move the MCS 2WNR to the E92 and get a MCS 3W Remote for the E90.
Also, at some point in time I'll install the Hotchins sway bars that are sitting in my living room, but one thing at a time!