Well... I would choose Kriede without any problem since it is light color. Or go for individual choice and order Ultraviolett from 991.1 GT3 RS.

GT Silver is safe Metallic choice as is Rhodium Silver. Guards Red, Speed Yellow, White, Lava Orange and Miami Blue will all look good on new GT3 as well. But, color choice is a personal thing. Just avoid Black. It is IMHO not thr best choice for 991.2 GT3.