No it isn't a gasket. The car does fine when normally used.
The block is o ringed to prevent gasket faillure.

The coolant going to the radiator is 96 degrees which is already on the hot side

the waterless coolant boils later and has less pressure. But you also need to have a good cooling system as it will absorp less heat than water

i have a cosworth radiator in it. Which i believe should be plenty enoug for the job.
most people with a tuned 2.8 cologne have heat problems.
big radiator bigger pump etc. all doesnt help.

im goinig methanol injection, bigger cooling surface and a lower stat. But also wanted to increase the pressure in the cooling system a bit