I’ve owned an RC-F, Boxster and a 996 C4.
One thing that Porsche always seem to get right is the steering. F cars can’t compete!
Also factor in that both the GSF and RCF are heavy cars circa 1800kgs. What’s a 996..... 1300kg? Add the fact that the F 5.0 litre engine lacks torque low down, and you’re dealing with cars far removed from the character of a 996.
As for RCF v GSF, the motoring press rave about the GSF and slag the RCF. I’ve driven several GSFs, and honestly, for the average driver, you’d wonder how on earth the motoring press can separate the two. Of course, the RCF was always pitched against the M4, and it was never going to win that battle.
Both great cars, but make the choice on your needs rather than what the press tell you.
One last point. RMS, IMS etc - you can forget all that crap in the world of Lexus 👍