Good adviceAbsolutely consult with a local bootfitter. I had Lange AC9s with a medium fit, and got a great episki deal on some Lange 120 FRs (low fit, 2 years old). Really like the boots, but they do have some interesting characteristics.
My Langes do not leak, and fit well (minor 5th metatarsal punch out). Heel pocket is great and needed no adjustment at all.
The 120FRs are about the same size as my AC9s, but fit better (and closer). The adjustability of the buckles/strap is good. The replaceable toe/heel lugs are fairly soft, which allows for better grip while walking, but they wear faster than the non-replaceable heel/toe on the AC9s. As for the shock absorbers, I can't tell any difference.
The FR does have a lower cuff than the regular 120, and if you have a long lower leg then the lower cuff feels easier to flex. (I'm 6'1", 170, long legs.)
It's not bad, but you may desire a stiffer feeling feeling at high speeds and/or in choppy crud. OTOH, there are times when the softer flex feels better.
Also, when it's warm out, the boots feel noticeably softer than when it's cold. Frankly, I like the boots better when it's below 37-40 degrees (I usually ski many spring days when it's above 40).
Overall, I might have been marginally better off with the regular Comp 120s due to the higher cuff, but since it would have cost me a couple hundred bucks more, I'm happy with the 120FRs.
The Comp 120s can be found pretty cheap now on ebay and elsewhere, but the FRs are tougher to find, especially since they stopped making them in a low fit last.