Everyone seems to be on the money with their suggestions. Definitly look at changing shocks. The only reason you have shocks sole in your car is to control the springs, nothing more. You have installed stronger springs therfore your old shocks cannot perform their only function in life.
Ensuring that the bushes are in as new condition will make a big difference but nolethane is not essential. It depends on what your willing to put up with.
Anti roll bars will make a big difference but make sure that you get front and rear to match.
Just to clear it up with what clint said re point 8. Offsetting the RCA won't increase shear load but it will introduce an eccentricity which puts a prying load on the bolts. The bigger the offset, the more axial load you are putting on them. you could probably offset them a little without compromising the bolts, but it is better to avoid it if you can.