What is the ride difference between the regular Bilstein and the HD and Sports Bilsteins. I have an '87 300E, and am contmplating keeping the original springs, but installing 420E antisway bars front and rear and 205/60/15 michelins on the stock rims. I would like a little firmer ride, would the HD or the Sports bilsteins be better with the stock springs. (Bilstein implies that the Sports struts are for use with shorter spring kits) I don't want to pound my kidneys loose, but would like less roll and a slightly firmer ride and handling.

Also, is a tuner chip available for this engine (M103)?

Thanks for all the great info from this site!

The sport version shock isn't going hurt the ride of your car like "low profile" tires could. The sport shocks have about the same damping rate as the HD ones, but are about 20mm shorter.
The advantage of "tuner" chips for KE_Jetronic systems are minimal because at fuel throttle the system is at full rich & there is a seperate ignition system that isn't affected by the fuel system.

Since you don't plan to change the springs then go with the HD version shocks. Hope you enjoy the ride.