JRZ is about as good as it gets. There are a handful of professional motorsports grade coilover systems in the world, and JRZ is one of them.
Until recently, JRZ only offered a double, triple, and quad adjustable coilover in the $6000 to $14000 range. We've used the doubles in our Time Attack GT-R, and every Porsche GT3, Evo, and STi that comes through our shop destined for serious track use.
Over the past few months, JRZ has been working quietly on a set of SINGLE adjustable coilovers for the high level consumer market. These coilovers use the same body, concepts, engineering, and technology as their motorsport line but with a combined single adjustment for compression/rebound. The result is a system that far exceeds the current shocks on the market, at about a $3340 to $4080 price with main and helper springs, and dividers. The pricing varies if you prefer a solid top mount or prefer to reuse your OEM hat for better sound isolation. For street use and fun track day use they can't be beat. There are even some teams using the singles for street class Time Attack. We will be testing the first set on the Forged 370Z in just a couple weeks. We are currently running TEIN Mono Flex's on our 370Z, so it will be interesting to see the differences between the two.
Here are some pics of the JRZ Singles for the STi as an example:
And for those wondering what a $14,000 coilover system looks like here you go. 
