Set on a board...but what size?

[Ghost_Rider_X]

well my 2010 board is going to be a NS premier F1-R. read a lot of reviews and after talking with a couple guys at the shop, sounds too perfect for the kind of riding i like to do. i'm 5' 10" 175 and primarily freeride and like steeps, speed, trees, and backcountry. right now i'm riding a 159. i'd like to drop down to a 157 for a bit more maneuverability, but i'm afraid i'll lose speed and power. i was told by a NS rep that i could easily drop down and still have the same feeling while increasing agility. the other part of me wants to step it up to a 161 and just have a stiff bomber board. perhaps sticking with the 159 is the right move, but i would really like to gain some maneuverability. not sure...any help would be great. sorry for rambling.

[Prophecies]

I am 5 feet 11" and weigh 150 lbs. I got the size 161 since I'd been using a 159 for the past 5 years, and I wanted something a tad longer. I don't think you'll notice that much of a speed drop if you get the 157. Two centimeters won't be a drastic change. If you need that extra maneuverability, go for the 157. But personally, I'd stick with the 159 if I were you. The only reason why I got the 161 is because I like a longer board.