After some advice from this site I ran my RDX for the second time on tarmac with 40wt oil all round and the 1.3mm pistons - car felt a good bit better but was 'nosing' under braking so I put 19lb springs on the front and put the shocks in another hole on the rear top. The car felt so safe I could really start to push it. In only two meets with the RDX I am were I was after a year with my Pro4 (and it was a great car).
I'm off to read up on roll centres now as I still think I can get the car to transition through the turns a bit better - i'll come back when I can explain it better - so watch out
And again thanks for the help guys.