I recently made a few mods to the suspension of my 240 and thought I would post
my reactions. Car is a '92 244 with Eibach springs and Bilstein HDs.

Previously I had 23/23 OEM swaybars (front 244 turbo, rear '79 242 GT). Poly outer bushings on front bar. This spring/shock/swaybar combination gave a really nice ride. Very silky and sinuous over bumps (though the Bilstein's could do with slightly less rebound stiffness) but with a lot of body roll in the front.

Recently added a set of 25/25 bars from IPD to reduce roll. Wasn't really expecting much difference, because the new bars didn't look much thicker--only about 1mm by eyeballing it. Effect was amazing though. Seat of the pants says body roll is essentially *gone* -- definitely the corner on rails thing. I suppose the poly center bushings account for some of that. Downside is that the car feels noticeably stiffer, has lost that really silky feel it had with the 23 bars. Trade off is worth it, but I think I'll try reaming some rubber inner bushings out to 25mm and seeing how those perform.

Have heard a lot of people express "Wow" reaction to IPD bars, but assumed this was mostly because they were upgrading from 19 or 21 factory bars. Was surprised to see this much difference moving up from 23 bars.

Then added a Cherry turbos strut brace and the strut to firewall braces. Lots of people say they don't feel much difference from this, but it seemed to me that this sharpened steering input. Hard to tell from SOP though.
IMO the Eibach's are the heart of the whole suspension. Very slight (and reasonable) drop, and an excellent balance of comfort and performance. Not teeth smashers like the more radical springs. Pity they quit making 'em.