Well, the OP has had plenty of accurate feedback, but I'll add my own $0.02, having skied both skis he is considering, plus all of the alternatives mentioned.
I found the Liberty V82 to be a rather "dead"-feeling ski that was adequate, but no more, in most conditions. No joy, no spirit. A better budget alternative for your size is the Salomon S/Force 9 (one sheet of metal) or S/Force 11 (two sheets): 80 in the waist, 170 length (80% of the fun of the Laser and I also preferred them to any of the DPS skis or Volkls mentioned above).
I own the Laser AX in a 168 length and ski it/teach on it 90% of the time. This is in all conditions except fresh powder over 10 inches. I'm a similar weight to the OP and find the 168 is more than enough ski, plus, as mentioned earlier, it's much livelier and playful than the 175 length. The Laser is a fairly firm ski that skis longer than its length. The 175 is more work and adds no advantages unless you are over 185 lbs. or so. If it's impossible to get the 168, go with the 175, but I'd look a bit harder.
OP: You know what to do, just do it!
Best!
Mike