I think I'm the first (or one of the first) on the club to try out BC Racing coilovers, so I thought I would post some of my thoughts and experiences with them.
While I was researching suspension options on NASIOC, I came across a lengthy review thread of BC Racing coilovers. I did a lot of reading, and they were getting great reviews. Since I did not want to spend the money lowering on stock-like KYB GR-2's, and Konis + Group-N top hats were out of my budget, I emailed Import Image to get a price quote on the coilovers. They fit perfectly within the budget (I don't want to give the exact price because it was a special deal at the time and I don't know if the vendor wants me saying what it was... but give them a call and I'm sure they will make you a reasonable offer.)
Anyway, the coilovers arrived, and the fit and finish was excellent. The installation was uneventful - unbolt the old strut assembly, bolt the coilovers in. The fun part came to dialing in the settings. Height is fairly easy to adjust, but it takes a lot of time to get it exactly where you want it. I set my height to 14" from hub to center in the front and 13.75" in the rear. I would not go any lower because I value my car's handling; however, if you want to slam the car, they are capable of going extremely low. You can also keep the car near stock height if you wish. I did not bother to have them corner weighted.
The coilovers have front camber plates. When I got my alignment done, I had them only set the front to 1.5 degrees camber and 0 toe. The shop owner said that he could easily have gotten 2 degrees out of the plates - keep in mind that I have a wagon, so I lose camber with the design of the strut body. In the spring I may go back for more camber, but I need to drive the car more to decide.
As for the drive, the ride is stuff. There is no way of hiding that since the springs are 8k/6k. Right now I am running at 6/32 front and rear, with 1 being the softest. I've tried 10 and 8, and I found both combinations to get a bit bouncy of moderately rough roads. On smooth roads, 10 felt great and was very smooth. When I autox next weekend on very nice pavement, I will probably bump the rates up to 16-20. I may try a few clicks softer for daily driving, but I do not mind the current setting.
The upside of the stiff springs is virtually no body roll. Handling is very confident with these, and I'm looking forward to taking them autocrossing and (hopefully) on a road course by the end of the year.
Now for the downsides: These are not Ohlins. These are not Bilsteins. These are not Konis. They do not have as much droop as the high end coilovers, and as a result the ride is rougher. I've read articles about the downsides of the "cheap" coilovers, specifically inconsistent valving. I did not have the dampers dyno'd, and I'm sure they are not perfect. They do seem to ride and drive well, and I will post more once I have started autocrossing on them.
Mine have been relatively quiet, but I do get the occasional squeak over rough roads. I think that is my rear pillowball endlinks, though, and not the coilovers. Overall, I am fairly happy with my purchase, but do not try to kid yourself into thinking that these will be as quiet, comfortable, and maintenance free as a standard spring and strut combo.