I went the Backdraft camber plates as the BDR shocktowers are narrow and won't accommodate caster adjustments. You may be able to pick up a degree or so by slotting the camber plates, but then even that is questionable because of the 4, 10mm locking bolts and where they are on the center tower hole.
I've been searching for Control Arm Caster adjusters for awhile now and of course no vendor ever really gives +- specs on the Heim joint style or the offset Poly or Delrin bushing types.
My personal quest is to dial out a bit of the current caster I have @ +4.4 and drop it to the lower side of spec which is +3.2 to +4.2 since I'm not happy with the heavy steering in corners.
But another issue I've had since day 1 on this car is a 50mph and up 1/4" steering wheel flutter. Removing some caster could accentuate it.
Although it was also there with old tires, I had these new tires road force balanced twice, removed tires re-indexed on the rims to lower the weights, Dial indicator runout checks axially and radially on the rims are good. Dial indicator runout checks on the pin drive adapters, The front end components are all new, Wheel hubs, rotors, Cleaned up pin drives, LCAs, Poly LCA rear bushings, Shocks, Camber plates, Steering rack play tightened up, steering column bushings and U-joints are tight and lubed (But I'm not happy with the mismatch in geometry in the upper and lower u-joints). Tie-rod ends are tight (1900 miles on the car) put new boots on them recently and found the grease still fresh and no Black Graphite (wear) but maybe next...
I have a set of Toe-plates coming since I have .44 deg toe out which does not help a bit.
In all not a real big deal and I love the hunt while troubleshooting.
A couple of shops do give a spec (this one is BS @ 10 deg)
https://www.driftshop.com/front-cont...t-e30-e36.html
calls out Centered to Offset
https://www.akgmotorsport.com/produc...w-e30-and-e36/
These appear to be the Backdraft source.
https://store.langracing.com/akg-fro...30-e36-and-z3/
All of these are typically non-lube teflon lined outer race bearings.