SO much in this thread is correct and so much is not. WAY too much to cover it all. But ..................
1) Terminal understeer IS easier to correct than terminal oversteer. In either case, the nut behind the wheel screwed up !!!!
2) Some understeer IS nice to "live" with. The Kappas have SOME understeer -- in street use.
3) SOME understeer is best in road racing or high speed conditions. MUCH more stable.
4) SOME neutral or oversteer is preferred in Solo type driving.
5) Chassis tune (other than alignment) is supposed to start with springs, THEN bars, THEN shock adjustments. Kappas come with SOFTER springs in front than rear, and without the bars would be loose. Kappas come with much stiffer bars in front than in back. (This is a matter of RIDE quality, not handling.) The bars induce the desired understeer that the supplied springs don't. If ONLY the springs were selected for handling, the avareage Kappa buyer would not like the harsher ride. Bars only marginally effect the ride.
6) Rebound (up to a point) will "control" springs, or rather what the springs DO when they uncoil. That is why more heavily spring cars have MORE rebound and LESS compression in the valving. Look at a car with worn out shocks that is oscillating up and down and you'll see what no rebound control does.
7) Once shocks, springs, and bars are selected and installed, (assuming tire pressures are set for best response) adding rebound at one end will induce TRANSITIONAL roll stiffness. Until the car has settled into its "steady state" in a given turn, more rebound in the front will cause tightening of a "loose" car or more understeer in a "tight" car. Conversely, more rebound in the rear will free up a "tight" car, and oversteer in a "loose or neutral car. Rebound is the touchy stuff and can really screw up a well tuned suspension package if one is not careful. Example; are car handles great (for a given person, car, and setup) and someone increases the front compression. The driver will have a car that will turn in better, but then start to push. Lee Grimes of Koni warned me of this last year at Solo Nats when he revalved my shocks, and he was 100% correct. And playing with rebound in front or rear may make things worse. Quite the balancing act.
8) Of all the respondents in this thread, Ben has it about right ------ for autocross !!!!!!!! A well set up Solo car can be a wonderfull STREET driver, but nearly a death trap on a raod course!!!
9) If you have adjustable shocks, DON'T TOUCH the compression adjusters, but start playing with the rebound and see how the cars reacts. Even at modest speeds the feel will change. Set the rebound at mid positions on all four. Drive it with some reasonable gusto. Mentally note the feel. Now, turn the fronts 3/4 firm and the rears 3/4 soft. Repeat. Stop, set fronts 3/4 soft and the rears 3/4 firm. Repeat. Come back home and post the results to this thread !!!!!!!!!!!!!!!
10) BTW, installed springs certainly CAN be used to change the handling if they are adjustable. In competition (race or solo) raising and lowering one end and/or the other WILL change the roll centers and how those ends "act". Also, preload matters !!!!!!!!!!!!!!!!!
There. That should toast a few folks, huh?
