I have been skiing the original (yellow) 1080's in a 177 for the last few years. I ski everywhere including park, trees, powder, etc. The new 1080's come in 171 and 181. I am having a tough time trying to figure out what size to go with. I beleive the tip, waist, and tail sizes have also changed (wider)for the new model. I am 5'8 and 135. I just don't want to lose ski performance by going with the wrong length. Any suggestions would be nice.