My KWs are still on the recommended settings for bump and rebound, and I'm happy with how they feel.
Having said that, anything would feel good compared to the King springs on stock struts like I had before, so I don't really have a good baseline to compare to.

Hey Purple,
 
I've got tien coil overs on my car currently and I had tien SS on a previous MR2. Adjusting the stiffness and hardness didn't really make too much of a difference for me. You notice it get softer etc....but didn't cause the back to sway or not sway. Even prior to changing over my shocks were completely gone and they didn't cause the car to do that. What tyres and wheel setup are you running?
I'd start by checking your bearings, I had funny handling when the bearings where worn and causing the wheel to move. Also check your rod ends as they may have play in them. Have a wheel balance done too as if its only happening at speed and your getting movement through the seat, you rear wheel balance is propbably out.

hmm its weird how the car feels, ill have to get someone else who owns a SW20 to drive it to confirm somethings wrong, im sure there somethign wrong, but since i was riding on cut springs previously i cant compare to a normal SW20 the car was really stiff and i liked how it handled before...
 
now of course on freeway speeds its a bit scary to try and test it
i have federal super street tyres and 17 inch rims with 35 offsets and a 5mm spacer on all ends 
wheel bearing have less than 5k on them
the car didnt do anything like this with the previous suspension, out of which one rear shock was blown..
didnt balance the wheels as it was not shuddering or anything
car is so low that its physically impossible for me to crawl under it, and im a skinny short dude.
ill have to jack up on the weekend and try and see what the hell is happenign under there

Wheel balance isn't only for a shudder, it can cause the back of the car to wobble. With a bad balance you'll feel the back move side to side at the rear. Interms of wheel tire combo. What are the tyre specs your running like 17x8 at the rear with 235/40/17's ?
By the way spacers can cause issues. On a lot of cars the hub centres the wheel not the bolts, so spacers can cause the wheel to be off centred. Also they wiggle loose. It's not the best thing to run. I noticed your in melbourne, you could give centreline I try, they are probably the best when it comes to race suspension and they have full equpment.

front 17x8 215/40, rear 17x9 245/40
the spacers are hub centric, and have been on the car with the previous suspension and i never experienced this issue
i didnt know that a bad balance of the wheels would cause the wobbling
ill have to look into that as well then
 
the problem though is, everything was the same on the old suspension, except for the fact i have now added RCA's on the car due to being quite low
i have however not installed adjustable tie rod ends thats some people suggest that has to be a part installed if your running RCA's

I understand what you mean by everything being fine on the old setup but now only with coil overs changed its handling really bad. I don't think the two are entirly related though. Like you said you had one blown out shock previously so even if these coilovers where bad you still shouldn't have these issues. You can check movement on wheels by jacking up the car and grabbing the tyre at the top and bottom and moving it back and forth. that will tell you if there is any play. The more you lower the car the move camber you'll get also. On a  side note I ran 17x8 up front with a 215/40 and the car handled terribly. Tyre was too stretched so it would tramline everywhere off bumps.

ok ill attempt to get under the car over the weekend and report back

purple5ive
one thing i also forgot to mention when we took the front camber tops off to fit adjustable ones, one of the sides had the orientation the wrong way, theres a small arrow on the top thats says forward, that was pointing to the back.. now this can probably change the castor a bit, just wondering now if the rear has also been installed the same way, and wethere that will cause this issue???
cheers

Unlike the fronts, the stock rear top mounts can only go in the one way.
 
 
 

I would almost BET this comes down to the roll center adjusters you've put on there..... too many things changed at once.

/\ im leaning towards them, but that doesnt explain why the front end doesnt do it???
 
might have to get someone who knows the sw20 very well, to take mine for a spin, and see what they have to say..
cant make it to the cruise on sunday, but maybe the dyno day might be a time for this