I have for sale a set of dunlop d212 gp pro 120/190 which had one trackday and heat cycle with loads of wear for a few more days
You so don't need slicks! 212's are same compound so are effectively cut slicks. I run 212's and have also run Dunlop ntecs and can honestly say I couldn't tell the difference. My advice would be to carry on with the 212's until they're finished then invest in the slicks but believe me they're only a dick extension!