So maybe a host of other issues. And likely combined with poor spring rates, nothing specific to parabolic vs regular leaf pack.
The parabolic suspension on my 88 was brilliant, it had more body roll than stock (but no worse than many coil 4x4s that have no ARBs). But it rode way better than standard Series suspension, handled great (chased a pack of Lotus Elises round the Elan valley, much to their surprise, with the Tdi engine, power steering and short gearing it drifted lovely in 3rd gear on the wet Welsh roads
). One of the lanes round one of the reservoirs was super pot holed and bumper. The 88 simply glided over them running at 20-30mph. The coilers in our group and standard suspension Series 1 where all having their teeth rattled out at 10-15mph and wouldn't go and quicker.
If you don't want the body lean, you'd need to look at fitting anti roll bars, as did the factory on late Series III 109's.
A couple more mods than just parabolic springs. But they did help enable it to flex like this, yet still be comfortable running across a stubble field at speed.
