Hell no. I rode the 178s for awhile and they were nice, and fun. But then they got fucked up so i warranteed them and got the 188s, and they were 10 times funner and 1000 times more stable, i 5'8" and use the 188s, but i weigh a good amount.
I have the 188 and im almost exactly your same size. Im also about 5'10 but weigh 150. They are a real fun ski. If you going to get them, get them in the 188 because its not too big for you. My buddy has the 178 and doesnt like them as much because they are too short. I ski on them everyday outside of the park and love them. As someone mentioned above, with added length comes added stiffness making the JP Julien (normally soft) feel a little stiffer at 188.