In a previous track event many moons ago I rode shotgun in a race prepped 911na. Yep its pretty fast as expected. I have passed all sorts of Porches on the track including a few 911's but in general their capability is stellar. It boils down to driver skill. That year I rode with a Porsche (he was also a drive instructor) I took off 5 seconds on best during the weekend after learning a few things.
If I had to point out a very important skill to master on Z's is preventing the Z to understeer on initial turn in. Trail braking is a valuable tool to make this happen. Once you get a few positive experiences with trail braking you will be kicking yourself you didn't try it sooner.