Thanks for the plug cvc
I've been meaning to do a more thorough review of the RS1 but just switched tyres which I need to get used to.
rismo, if you like the stock ride height of the car then you'll want the fixed height RS1 damper. The height-adjustable one's max height is noticeably below stock. I have the fixed height one, with AC Schnitzer M3 springs (made by Eibach, though I do not know the rates because ACS keeps them 'secret'), full M3 suspension, Quaife LSD, Rogue toe arms, Ground Control M3 camber plates and Powergrid sway bar end-links plus track alignment. I run Michelin PSS on the street (19" wheels, 235F/265R).
The progressive springs I have are ideal for street and track dual use. I forgot to turn down my RS1's from full stiffness yesterday and it's no big deal, still comfortable. I may switch to a stiffer spring in the future with a linear rate as the ACS springs are on the soft side. The JRZ damper is unique in that, because it is high gas pressure and has a large piston rod, has a certain amount of spring rate built-in. Therefore you can run a slightly lower spring rate and still get the benefit of something a bit higher. The RS1 is an example of a damper run in classes of race cars that restrict spring rates - it's all about the damper. The gas pressure is adjustable so you can change how powerful they are just by adjusting that.
The guy who founded JRZ is the one who pioneered modern damper technology. I read his book and I don't think there is a 'better' damper technology out there for any quantifiable amount of money. The way JRZ approaches damper technology goes against what a lot of race teams think and after using them ... JRZ is right.
Everyone who has ridden in my car has said "there is something different here" even on the street. I have had several professional drivers take my car out on the track and critique it and have yet to receive anything but good comments... and I am rather pointed when asking questions about its setup. If there was something this car needed suspension-wise (other than going with slightly stiffer spring rates), I am sure I would have heard about it by now.
PM me if you need a hookup for the RS1s, I can put you in contact with a race shop that can give you more advice than I can (VAC Motorsports ... second to none). JRZ isn't the only one to consider - also look at Nitron and their R1 kit. I had a ride in a Nitron-equipped car around the track and it was good stuff.
Edit - here's what the ride height looks like: