I did a S**t load of research on the subject a couple of years ago. Found good threads on G35driver
Out of it the opinion is Aragosta, Ohlins, Bilstein, KW, Tein in that order for quality of the above mentioned manufacturers
As for ideal setup & spring rates for Australian roads the Bilstein P9 & 10 were best suited.
I went for the Ohlins as I don't want to be replacing parts or rebuilding them in 12mths and I got a good deal
BC's don't get much of a mention
FWIW quoted from G35Driver:
KBee
Coilover: KBee
Style: OEM
Spring Rate: 12K/12K (Swift Springs)
Drop potential: Frame Banger
Adjustability: Height is as easy as any coilover. Dampening for the front is easy, The rear needs to be off the car.
Stiffness: Ridiculous on full still. Pretty comfortable on full soft.
Harshness: You can feel the road beneath you, but you don't hate it.
Price point: These are extremely rare JDM coilovers. They are only available in Japan. @$1200 US