Yeah, the trend in snowboarding is toward smaller and smaller, but for your riding style I don't see a problem here. It's definitely big, but if you like to ride balls to the wall and a lot of powder, then go for it.
As for carving, it'll be awesome.
Fast turns? Not sure what you're talking about here. If you're talking about big sweeping turns going balls to the wall, then again, it'll be awesome. If you talking about being nimble in the trees, well, it's a big ass board. The RC profile will help here, but it's still a big ass board. You're gonna have to muscle it around a bit.
Center of gravity? It's not going to make a bit of difference. The weight difference between a 159 and 164 is going to be negligible in terms of COG.
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