To be clear, the SSK is a mod to an OEM Carrera box (But perhaps standard on the GT 997.2s?), which the Numeric replaces with an entirely metal-on-metal system.
My analogy with suspension bushings is apropos, precision can come with a cost.
Caveat emptor.

 

SSK was an option with plastic hardware. Gt shifter was standard non short shift but with metal hardware like the function first shift right solution. Numeric combines all 3 into one with adjustability in height.

 

Since you have direct experience with both set ups on the same car, and I do not, curious what you specifically mean by ‘slightly better in regards to shifting”.
Precision? Soothness? Effort?
Thanks in advance.
By the time one buys a new OEM SSK and the FF SRK, with any install/adjustment paid labor…end up almost a wash $ wise with either choice.

 

Overall smoothness and improvement on 1-2 shifting. Also I liked the idea of a drop in unit vs upgrading components. Also the numeric is a work of art!