Mine is a '17. At that time 12x12 gained about 4 gpm on overall hydraulic flow, electronic 4x4, E-pto(540 pto speed at 1600 rpms instead of 2250), park gear instead of a parking brake, and I believe there was one more thing that I can't remember now.
I don't know that I gained anything. E-pto is useless because you need high rpms for DPF. Electronic 4x4 over manual, I don't see any plus or minus really. I never use 5 or 6 for field work and can use high side for traveling. GPM might be the only gain but I don't know if I would notice it, if I compared it to standard
Good luck with your decision, I had to order mine because I got an open station and they are normally 8x8
So, in your experience, you dont see the benefit in the 12x12? If you were buying again, would you get the 8x8?
Thanks