Just tested this weekend a 2018 Angrry 165 T4 vs a 2016 NFCE 170 T3 on a ultra firm, ice and fast conditions where most of the carvers were chatting out, both boards have a vsr 10/12/11 approx and 20 waist.
Both boards were gripping like hell. Felt confident at all time with very agressive lay down carving. Lost the edges once or twice on 2 full days riding (10 to 4). Have not change my style vs hero snow.
Felt the t4 is having more torsionnal stiffness and felt that it was just a notch better on ice. Obviously, it is not a world difference between both boards but that can give you that extra bit confidence that makes the difference.
I owned 5 diffent models of T3 coliers (stubby’s, Monsters, nirvana’s) and always wanted to compare T4 vs T3 on tough conditions like I did, even if the board models are slighly different.
To answer your question, I would go for a T4 if I had to order tomorrow.