Have you considered running 2xsets of wheels track and road it's a bit of a heavy investment but will pay dividends
Toyo R888's are road legal and good on track.
http://www.toyo.co.uk/tire/pattern/proxes-r888
most road tyres won't hold up to serious track use as when they get hot they wear like a b**ch
depends on what's the most important track or road use ?
No you won't gonna have to go for 195/50/16 bud
Thanks Bob