Your sorta half way there......
Intel makes the driver, akas the 15.21.22.... or whatever it is. Then they give it to all their customers... Sony takes the driver and adds AND/OR subtracts stuff to it. |they add the 8.15.10.... Basically they add the first 8 to the Intel driver to denote its a Sony changed one.
So honestly, Sony won't be any better a improvements to gzaming vs the Intel vinnilla one. But it may be better at doing Sony system stuff better.
I would say, go ahead and run the Intel driver, and if you find issues go try the Sony version.
Edit
Looks like i lied to you.... The 8.15.xx.xx.xx is also a Sony number, the newest driver is also know as 8.15.10.2246
The current Sony is atleast 3 drivers old btw