i have a 158, i weighed 175-180 at the end of the season, and it seemed like i could weigh way more and still be fine on the board. it almost seemed too big at first, but i was riding on a smaller mountain with narrow trails/trees, and i was used to a park board. the effective edge is pretty long for the overall length of the board, so i think you'll be fine there. the only thing i would worry about is the torsional flex in the middle of the board. if you're not railing carves going mach speeds, i think you'll be totally fine on it. it's definitely not too flexy overall, and the carbon outside the bindings makes it pretty stable, so i don't think your nose or tail are gonna be too sloppy on you.
don't take my word only though, just offering my limited advice as i have the board.
Well, I'm coming from am '07 K2 Union 164w, full camber park board, way too big. I was thinking of the 161 SL, and I can't believe 3cm is really going to make that much difference. It's still going to be light years ahead of what I ride now... which i get up to 50mph on my gps (which I know everyone hates, but it's a relative number).
Epic, gimme a couple days, let me mull it over, and if you still have it, I'll PM you.
"my only interest in statistics is in not becoming one"