When considering shortened springs, give consideration to the fact that reducing the ride height alters the driveshaft and U joint angles. You may need to make adjustments to the torque rod length to bring the U joint flange angles back into agreement if you do a more drastic drop. Reducing the ride height also causes the panhard bar to push the rear axle off center. You may need to alter the panhard bar or get an adjustable one to shorten it and bring the axle back to center. The more drop - the bigger the problem!
Finally, this is mostly for appearance. On a dual wishbone suspension when you shorten the springs you drop the center of gravity; but, you also drop the roll center of the vehicle so the moment between the roll center and the C of G remains the same, or worse increases. Net effect is that amount of vehicle roll does not reduce (or may get worse); but, your perception of roll may be reduced because you are a nudge closer to the ground.
My direct experience is with the Lejofors short springs on a 142. Very stiff and ended up shaking the car badly on uneven surfaces. My Wife refused to ride in the car. Very little body roll because the spring rate was so high that the suspension did not compress much during cornering. I switched them out for the Amazon Car's fast road springs which are progressive in the front. Much nicer and the car is not developing rattles from driving on our less than perfect road surfaces.
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