Thank you Exonian, Paul70 & clubsport for your contributions - all extremely helpful and greatly appreciated.
Agreed with the stock CS suspension - lovely OEM comfortability, but yet seems to keep the vehicle much in check. Thank you Exonian for the information with regards to the DCC setup on the CSS. It makes sense to maintain the OEM springs and to just improve the chassis, brakes and upgrade tyres as per Paul70 & clubsport recommendations. I think a baffled sump wouldn't go amiss so as to prevent oil starvation on an occasional trackday.
Thanks again guys, I don't know when I'll crack on with the car, but will keep you posted as I dive into my first VW project!