Lol, I meant chuck some on and see if they fix the vibration.

@Redtarga  - Eibach Pro + Koni adjustables is what I have and after thinking more about bump steer, I believe what you say about them not being too hard. Why I say that is because if 1 wheel hits a bump, I get a big yank of the steering wheel but the car goes over the bump just fine. It is when both wheels hit that the suspension travel is restricted  by the hubs which are unable to rotate around the steering axis in their bump steering fashion.
 I had a look at bump stops, thinking they were just a metal protection, but it seems they are 'clever' in max travel cornering situations. The situation I'm describing is going straight ahead.

Thanks B24,
 I got an inspection done yesterday and the report came back that I need:
 Left Front Wheel Bearing
 Both rear control arm bushes
 1 rear castor bush.
I had expected more especially in the steering rods, but I have already (<2000kms ago) replaced the left front outer tierod.
 I just posted on the Ordering Parts thread to see if a group buy for all the bushes was still happening.
 I will also be buying some bump steer correction bits to compensate for the 1" drop.
 

Hi RT, well I don't understand. If there is no bump steer with a 1" drop, then wouldn't there be some with the
stock ride height. Unless the pivot points were aligned, which I don't think they are.
 Anyway I will fix up the bushes and wheel bearing first and then check the behaviour before proceeding with
the adjusters/spacers.
  I'm not sure the wheels being out 10mm over stock (35mm offset) contributes to the bump steer but it certainly accounts for the wheel bearing. Will be sorting better wheels also. Will check your suggestion - Nissan 40mm offsets.

@5sgte - here are links to some significant analysis of SW20 suspension geometry, front and back.
http://wilhelmraceworks.com/suspension-analysis-links    A lot I understand and a lot I don't.
Mainly modelling software results with some real world confirmation.
My 1990 has been lowered 1"  (Alex models 3 ride heights - stock, 1" & 1.5" down).
I need to go over it again but it seems from 1st read, I may just need the front end rca bits.
The rear end bump steer (+/- variation in toe) is minimal between stock and 1".
 

5SGTE
B24, I'd be interested in your experiences testing and measuring bumpsteer on an sdub.

I had these on file but it could be a task to find! One thing for sure , is its was a lot more settled to drive after setting up the bump steer.

kameleon
I see bump steer talked about here but only B24 understands what it actually is!
 
Get your wear issues sorted out then a good alignment. Which is basically all you need.
 
B24 at what point did you have toe out and in when doing your plots? Although zero is the sort after figure i have had great results on other cars by dialling some bump rather than removing. This could reduce that huge height stack you had to do to get zero bump on the SW20 chassis and make the chassis more stable at speed.

Thanks mate. 
 
When I checked the bump steer it was set at the toe alignment that I planned on using. The next time I fine tune it, I would check the bump steer in numerous toe settings just to narrow down the optimum set up. 
Adjusting the rear caster through a number of settings also shifted the bump steer plot so in the case of the rear of the car being less flexable for bump steer adjustment, you can set the caster to have the bump steer being closer to neutral in a set range. I managed to set it up in this way so the bump was neutral until the last 30mm of travel where it would then toe in. The rear bump on the race car does not toe out an any stage of travel. It was -4mm overall (if I recall) then finished at -6mm on full compression on the bump stop. That is total -mm from the front of the rear rims
The orginal front toe link stack was never calculated. I simply had a guess then had it made then tested it. IT was way too big, effected the steering input, was a bit vague then broke. Once I returned to the set up in the second photo which was used at MTC /Wakefield 300km, it was a sound set up in comparison. This is the same link used by EVO65 used in the WTAC SW20. 

TwoDogs
@b24 - how much lower than stock is the car ? 

I really don't know as I have never measured the stock ride heights. It is pretty low. Photo added to give you an idea