Well, it's now been a couple of weeks since i installed the coilovers and i've managed to do about 500 km with them including 2 track days and a weekend of mountain road carving, so it's about time to write a review.
Just to make sure everyone is clear, these are the non-sport model with 9kg front and rear spring rates.

First Impressions
First of all as you would expect from a company like HKS, the quality is bar none. After a thorough optical bollocking i couldn't find any defects in the workmanship of these coilovers. Needles to say they were VERY well packed. Some people say they come preset from factory, but mine were not set to the same specs that the instructions stated they were, but i don't really care because i re-adjusted them to my needs anyway.

Installation
The installation was very straight forward and i'm very impressed that they went to the effort of finding what the torque specs for our car were. I cross checked them with the workshop manual, and they were all bang on. In all it took me about 3 hours to do the install.

Ride Height
The ride height adjustability is quite good. The front can go from stock height to -25mm, and the rear can go from stock to -49mm. On the photos below, i still don't have them set to their lowest. I can still get another 3 turns on all corners which would be about another 5mm drop. Also bear in mind that the springs still haven't fully settled.

Ease of Adjustment
The height and damper settings are very simple to adjust. You will have to jack the car up in order to reach the threaded body of the shock however. If you are planning on adjusting the rear dampers, make sure you do it before you go on the track, as when the brakes get hot, you will burn yourself. I learnt the hard way. The front dampers are adjusted with an allen key or the provided HKS adjustment ****, and the rear dampers have a built in **** at the bottom of the damper.
I must mention though now, that even though HKS says it is a 30 way adjustable damper, i have counted 33 clicks on the front of mine, and 35 clicks on the rear. Don't know why.

On the highway
Well, i must say i am super impressed at the spectrum of these coilovers. On the highway, i had them set to 5 - 10 clicks from full soft, and these things are COMFY AS HELL. They iron out bumps and dips fantastically. The only thing that still jar the car somewhat are potholes, but i think that's pretty much inevitable. Even so, it's not that bad.

Around town
Again, same settings as on the highway, and still very comfortable. Low speed bumps and dips are totally ironed out. The best way i could describe it, is probably better than stock.

In the mountains
For the curvies up in the mountains, i had the dampers set to half way. 15 clicks from full soft. I didn't want to go any higher as the roads are quite rough and there are lot's of fast transitions with nasty road imperfections that you cant see until your on them. Even with the rough roads, the car was never unsettled. The car felt planted at all times even when the going got really rough. The crispness of the turn in was was awesome, the car gave so much feedback and inspired so much confidence. There where a couple hairy moments where i thought i was going to loose it, but the car just held. (i was pushing hard, probably harder than i should of). Needless to say, i was very impressed with them.

On the track
I had a track day on thursday, but i hadn't had an alignment for the track done so i was suffering from a bit of understeer. I tested the coilovers with the settings the same as the mountains, and found the coilovers to be a bit soft for the track. I adjusted the damper settings up to 20 clicks from full soft, and even though you could definitely notice the difference, it still wasn't performing as well as i'd hoped. Unfortunately the rain came in and i called it a day.
Today i had the chance to go again after adjusting the car a bit more. I had a re-alignment done, and took the sway bars stiffness up a notch, and set the dampers to 25 clicks from full soft. Wow, what a difference that made. These coilovers can definitely perform on track with the aid of some decent sway bars. I'm not going to say they are bred for the track, because they are not, but they definitely hold there own. I could have set the dampers a bit stiffer, but there where a couple of areas on the track that they had been fixing that where still a bit rough, so i was happy at that setting. As a comparison, the track is quite a tight one, mainly geared at handling, and i was able to keep up with a stock lotus elise with no problems (how hard he was pushing, i don't know, but enough to get me working hard to keep up with him).

Conclusion
These coilovers are definitely the jack of all trades. They are incredibly comfortable for daily driving, yet they can still do a great job on the track. A lot of people say that there not really geared for heavy track use, but i think they did a pretty damn good job. I will be running them competitively next year in the 2010 timeattack series, with some more suspension work and some weight loss, so we will see how they do.
All in all, i couldn't be happier with these coilovers.

 

Good write up. Have you owned any other type of coilovers to compare?

 

On the 350Z, i've only had the stock suspension, H&R lowering springs, TEIN S-Tech lowering springs, and now these.
I've had the KW coilovers on my last car, but not really a fair comparison.