I have Eibach Pro-kit springs (so car is lowered down to the limits) and Bilstein HD shocks but as car is used for roadracing occasionally seems that Bilsteins are not up to the task on the track but stiff enough for the daily driving. I am looking at Koni adjustable singles or doubles but not too sure which one would be the best for my application - your input would be highly appreciated.

 

Single

 

^^^^^^^^^Like he said.

95% of owners dont need the DA

 

what is the difference between the two?

 

Doubles adjust dampening as well i belive

 

that is the point - I need car to be reasonably soft at street and stiff on the race and do not need to lower it more - will singles do it?

 

Your springs are what'll make it stiff. The shocks just dampen the spring's motion.

Eibachs are known to sag in the rear and ride the bumpstop. NO shock will help that.

 

Singles are adjustable for rebound only, doubles adjust compression and rebound.

 

Does that mean in simple terms that ride stifness is adjustable as well in comparison with singles? I am lost

 

Understand that when you talk about "stiffness" it involves spring rate as well as shock absorber compression dampening characteristics. Doubles do let you adjust compression dampening but to really change stiffness I think you would need preload adjusters on the springs.
You might want to talk to Sam Strano at stranoparts.com

 

Okay, after talking to Sam Strano singles it is. The only question is - will there be any noticable difference in comparison with Bilsteins? Anyone has any experience in comparing those two for roadracing/daily driving?

 

I've never roadraced but the Koni's are by FAR a much better shock than the Bilstein HD's.

Steering response will be quicker, less understeer that's for sure...
Your vehicle will feel better, more comfy ride, and yet you'll be able to drive her into the corners deeper than before.

It's a night and day difference...

I'm SURE you'll be quite pleased.