I ran KYB's on my Challenger with 1.12" torsion bars for tens of thousands of miles, they were new and on my car when I bought it so I left them there when I installed the bigger bars. When I put my Duster together with 1.12" torsion bars I installed a set of Bilsteins because I needed new shocks. Now, keep in mind A-body 1.12" bars have a 300 lb/in rate, and E-body 1.12" bars have a 270 lb/in rate.
Guess which one had a harsher ride? I'll give you a hint, it wasn't the Duster. Even though it had stiffer torsion bars, 18" rims instead of 17's like on the Challenger, and is at least a few hundred pounds lighter.
So yeah, even for a street car the Bilsteins are better. In fact, it's MORE noticeable on the street. The Challenger handled well with the KYB's, it just had a harsh ride quality to it. I've since gone to Bilsteins on the Challenger, and Hotchkis Fox shocks on the Duster. For really big torsion bars, like the 1.12's on the Duster, the Fox's are a bit better than the Bilsteins. Not as big a difference as there is between the KYB's and the Bilsteins though.
