Replying to Lenght

Ok.
Me (178cm) and my brother (184cm) are going to buy a pair of fujatives together. im mostly hanging out in the park while my brother is more of a racer/allround guy. I would like to get the 169s but my brother thinks the 159s is the better choice. im now skiing on a couple of völkl 168 and i really like them, both the lengt and the ski. Anybody got some suggestions on how to convince him that we should get the 169s.

Anyway, if we get the 159s do u think i will notice any difference, compared when im riding my völkls 168?