The spring shims will have no noticable affect on ride quality at all, they merely set the static ride height and as mentioned this can only vary by about 15mm from the highest to the lowest shims.

The shim's aren't your problem, I would start with a 4 wheel alignment and get the specs from that then you will know what the problem is. This should also uncover any worn bushing etc.

If the negative camber is wearing the inside edge of your tires then you can either fit a camber kit on the rear or increase the ride height by fitting the largest shim, as this will only provide a small increase it probably won't change the amount of camber adjustment much.

What tires and rims are you running? The sway you refer to could be a number of things but a wheel alignment should uncover most of it then followed perhaps by a wheel rotation.

Thanks for the comment Ksing44, your car is awesome as well. I am going to monotone next, it looks great on your car.

Cheers
Matt.