I've had the Bilstein PSS9 for about 6 months now, and can give you a quick run down. A lot more details can be found by searching the topic.
Very easy to adjust the height and damper at home. The height is adjusted by turning the threaded spring holder which subsequently moves the spring up or down. The damper is also easy to adjust simply to raising the car. The knob for the front is located directly below the damper, and the rear is located on the side of the damper facing away from the wheels. I attached a picture of the front damper adjustment for reference.
I've had the opportunity to drive the car in many different driving conditions, at different settings. The first 3 months it was driven on 9 all around (1 being the stiffest). For being the softest setting, I was surprised with the improved handling characteristics over stock. However, going through a turn at 45 miles plus seemed like the car leaned too much, more than you'd want. After changing the car to 4, everything I liked about 9 was dismissed. The handling was very predictable and stiff. Body lean/roll was essentially eliminated (at least what you'd feel on the streets), the car would not dip under hard braking or squat under hard acceleration, a very neutral feeling car. Cornering was where you'd really feel the suspension in action, with the rebound being almost immediate. You the driver just feels more confident with maneuvering the heavy beast. Currently, riding at 5, the car is dramatically less stiff than at setting 4. I haven't noticed a big difference in handling characteristics at similar conditions as setting 4, so I'd say between 4-5 under normal driving conditions, handling improvements are the same.
Of course at 9 (softest setting), the ride was incredibly comfortable. I did not encounter any driving situation that was uncomfortable. I drove the car through San Fransisco, Los Angeles, and everywhere in between my road trip between the Northern and Southern CA cities. 9-being on the extreme soft side of the suspension's capability was too soft for my taste. At damper setting 4, it was very stiff. I really like the feel of a stiff suspension, and 4 hit the spot. However, over dips in the road, you'd feel a sudden "dip" in the car as well. Reminded me of how a roller coaster takes a small dive and your stomach just sinks. Generally speaking, it probably wasn't the most comfortable setting for my passengers. Driving over road imperfections could cause motion sickness, depending on the severity of the road. Currently, setting 5 offers a little less road-feel than setting 4; it is still pretty stiff. I'd say the perfect setting, in terms of comfort, for the PSS9 lies in the 6-7 range. Of course this depends on the road condition. You could get away with 4-5 if you only drive on freshly paved roads
Because of the ability for you to adjust the height, the stance should end up being perfect given your personal preference. You cannot go wrong since you can adjust it any way you'd like. I believe I am 14 7/8" all around (from fender to middle of wheel). I'm not positive, I'd have to remeasure for accuracy.
I chose to have these done at the local shop (thanks Kurt!), I'd say the install was easy
. But despite the fact you have to remove the entire rear deck to access the rear suspension, it is a real straight forward install. The instructions seem no different than installing suspension on any other car. Of course, with certain tools (lift, air tools, etc), it certainly makes the job easier. Should range from 6-10 hours depending on experience level.
The PSS9 offers easy adjustability of damper and height settings without having to remove any interior pieces or use of special tools. The range of damping that is offered (1-9) is plenty to be able to tailor to your own personal preference. Most importantly, handling characteristics are greatly improved with this mod. I can't comment about Dinan, but I know Dinan comes pre-set in terms of offering a comfortable ride. Until I find the optimal setting, Dinan has that advantage of the PSS9 (not a bid deal for me, however). Also, others have cited that Ground-Controls allow clearance for those running rear wheels in the front. I think I remember members reporting there was clearance issues with the PSS9 barely fitting rear wheels up front. Since those were not my concerns, I am 100% satisfied with the PSS9. The fact that I can adjust the damper from under the car, in my garage, at any time I wish, is really convenient for me. I don't think you'd be unhappy with the PSS9 if you chose to go with them. :M5thumbs: