Hello,
Can't say much about the 173, BUT, I have a 168, it is AWESOME:1luvu:! I can really crank on it and it holds. NO nose flop, nothing, it is a great board. A friend of mine has the 173 and he loves it (he searches them out). He goes about 195, and is a VERY aggressive rider. He uses it to prove you don't need and alpine deck to do VERY well in a course.
Just for info. I ride mine with a soft boot setup, my friend rides his with a hardboot setup. Either one works VERY well on these boards.
Hope this helps.