There is so much demand for tuning these vehicles I have no doubt an easy tune will come.
But a 435HP non blown 6.2 is already a decent utilization of the engine, I doubt the gains are THAT significant and the reasons for tuning are more for flexibility, DFM disable, big one for me is unlocking my cameras while driving (using my side cameras essentially eliminates my need for trailer mirrors when I was playing around with my brothers car hauler on the weekend ).
But yea. C63’s can totally hit 300.