This is what I've tried on my 99 HB:
1. Eibach Pro-Kit with stock shocks
2. Eibach Pro-Kit with Koni Reds
3. Skunk 2 CO with Koni Reds
And now,
4. Eibach Pro-Kit with Koni Yellow.
So with all that money and time I've spend on all those stuff, here's my conclusion:
1. Nice ride and improved handling, but dampers not aggressive enough; nicer drop & fender gap, better than stock
2. I have some problem with set up. The ride's fine and the dampers are a bit firmer, but fender gap is HORRIBLE! The rear gap's okay (tight 3 fingers) but fronts are terrible. It's so large that I could fit my whole fist in loosely. The ride high is way more in the front than rear and looked aweful. Unfortunately Koni Reds aren't adjustable both frimness & ride heights.
3. I then got a set of Skunk 2 CO with Koni Reds and the handling is awesome! Quick steering response and almost no body roll when cornering. Since the hight was adjustable, I got it where exactly I wanted it with nice, even fender gap all around whithin 1/16"! The ride's not harsh at all but it's kinda bouncy, especially over large humps. I thinks it's due to Koni Reds' low damping rates which were no match to Skunk 2's higher spring rates. Again unfortunately, Koni Reds cannot be adjusted - at least without disassembly the whole suspension.
4. Finally fed up with my head hitting the roof at times on freeway with Skunk 2 & Reds, I bit the bullet and got a set of Koni Yellows. Instead of continuing with Skunk 2, I went back to Pro-Kit. And the result? TOTALLY AWESOME!!! The handling's not as great as Skunk, but still very, very good. The ride's not harsh and most importantly, the bounciness' gone. There's infinite adjustment with damping firmness with the Yellow and I found the setting I like the best both performancewise and comfort. Since hight also can be adjusted with the Yellow, I got nice even tight 2-finger fender gap all around and the ride hight and stance looks aggressive and great.
Final word? Save your money and just get Pro-Kit & Yellow. Even though the Yellow are kinda expensive (~$600) but it worths every penny.