Off the shelf shocks for these cars ARE NOT valved correctly for heavy duty suspension. Once you even get close to 1" torsion bars your spring rate far exceeds the shocks ability to dampen the springs.
Ideally, the spring and shock need to be matched so that the suspension is close to "critically damped". This means that after an impulse (say a pothole) the suspension travels its full distance (given the size of the impulse) and then returns to its normal ride height without traveling in the opposite direction and without multiple oscillations.
Typically on cars you want the shock set up so that its a little bit shy of critically damped, as most folks will find that a little on the harsh side. Overdamped means that the shocks will control the travel of the suspension and not let it travel its complete range (think air shocks), which gives you a harsher ride and is bad for the suspension. Underdamped is what most suspensions end up being, with the extreme example that everyone is familiar with of driving a car with wiped out shocks, you hit a bump and the suspension just keeps bouncing as you go down the road.
The Bilsteins are a BIG improvement for car with larger torsion bars. I haven't tried them yet, but Hotchkis also worked with Fox and now has a set of shocks out that are custom valved for the Hotchkis cars (ie, big torsion bars). They're supposedly much better matched to the larger bars than even the Bilsteins, so they should be very advantageous to those of us running much larger torsion bars, 1.04, 1.06, 1.12 etc. They're like $550 for the set from Summit though, so even the Bilsteins are quite a bit cheaper at ~$400 for a set. But if you've spent the money to put big torsion bars, sway bars, frame connectors and everything else on your car to make it handle, you should finish the job with a set of shocks that's matched to everything else you've already done.
