Coilover Recommendation

[flipm3]

I am just about ready to finally step up and try out a "high end" damper and was looking to seek some advice from the good people of CSLRegister.

My E46 M3 is primarily a road car, but does see roughly 5 track weekends a year. In all honesty, I prefer a damper that will be comfortable on the terrible roads I frequently encounter, but still offer optimal performance at a lowered ride height.

I have gone through several "entry" level coilovers and their valving just really left something to be desired.

My current list of choices are the following in the priority order:

1. Ohlins R&T
2. Motion Control Suspension Single Adjustable
3. JRZ RS1
4. Intrax IK2
5. Nitron R1

I'm reaching out to you all to mostly hear your feedback on the comparison between Intrax and Nitron. Information and knowledge is rather limited out here in America and these two seem to be a popular choice in the UK and throughout Europe.

My car is driven all year round and I would prefer something that is a bit more resilient to snow/salt.

How often do these setups need rebuilds?
How are their street characteristics?
Any downside to running a true rear coilover with a reinforced rear shock tower?

Any advice would be greatly appreciated.

Thanks!