I know its not a C3 but I put Kumho on my 90 C4 after a NCLE member recommended them.
These are on STD OEM wheels and have been good in the wet and dry.
These are 275/40 R17, whilst a low profile wider tyre than yours, I've had her on three wheels several times over the top of Mt P
Bathurst, and they felt good, hung on, no screaming. So the brand and tread is OK.
Oh! And they were ordered by Tyre Pro Minto and fitted/bal for I think $160 a corner. AND i pushed for the freshest date.