One other issue on the LGX - there are some long term implant patients (like me) that experienced tunica albugina failure. This is due to the connective sheath tissues weakening over time and causing failure. So to the guys who are trying to get a larger size by stretching the tissues past normal - just be mindful of this. I know others who have experienced this failure as well.
Generally speaking, those whom I am in contact with who have the AMS 700 LGX do, at least, retain most of the pre-surgery length. None of them (manufacturers) will tell you it will increase over your original length, although the website you referrd to does give you that indication. It does not work that way. I do know (personally) of one guy who has this model, and he still experienced shortening, and of course he was dissapointed. So, as "they" say, it really depends upon an individual guy's anatomy... I think. It also depends upon the experience of the surgeon. My doc wanted to use the 700 CX. He said it is more rigid than the lgx. I went with his advice and have the CX. I did experience some shortening, but I'm not sure if it was actually post prostate removal or post penile implant installation. I did increase in girth size, at least, and wife says that's good.