Best set up is very subjective, ive got standard shocks, prline springs and a whiteline ARB, however you may not like it as the Whiteline ARB can make the rear end more 'lively' (TBH when it was on its hardest setting it was too lively for me it was quite twitchy).
And for me this is an ideal b road set up soft enough to absorb potholes without breaking my spine (im getting old!) but firm enough to feel whats going on / have enough grip etc.
What do you want from the car?
As said before from the sounds of it something is wrong with your car, check your shocks for oil/ leaks and your springs to make sure they haven't sheared (as its happened before on mine).
Then if something is noticeably broken change it / replace it to see if you prefer how it should feel as standard before you go changing bits here and their that may not need changing? As its a very capable car in standard guise