George:
What TC typed, except for the following:
You've got swing arm suspension in the rear (non-IRS) so a rear sway bar won't work. What you need back there is a "Camber Compensator" which acts differently than a sway bar (for your suspension) while still atempting to give a flatter car (less body roll) in the corners.
I'm undecided on the lowered spindles....I don't have them and, even though it's lowered a little (not in the weeds by any extreme), it still handles like all the other "real" 356's i've driven. If you want a weed beater, then go lowered spindles. If not, then I assume you already have a lowering kit on your front torsion tubes, so just drop it down to where it looks good, and make the rear match it for height.
Now, the important part: VW front ends are susceptible to the dreaded "BUMP STEER". It sounds like that's what you've got, since you state that it moves all around over bumps. Once you get it lowered to where you want it, take it to a competent front end alignment place and tell them to align it as a 1966 VW Sedan if it has king pins in the front, or as a 1969 VW Sedan if it has ball joints. Tell the tech it has had bump steer and please correct it - he'll know what to do. also, get a dual set (four pieces) of caster shims for the front - the alignment tech will need them when he does his thing.
I also tried a brake bias valve for a while and didn't notice any difference.
gn