WRL: Here's another opinion; you are obviously young and did not grow up with a MK VI, so IMO you should have no need for one at this time. Later, after you've made a fortune as a sax player and can indulge yourself, you can buy as many of them as you want
. But for the forseeable future, please forget about a MK VI. Start going around and playing new saxes until you find what you want - it's not only fun, it's very enlightening. Saxes today are not only the best they have ever been, there is also a huge selection of pro models. When I was young, there was mainly Selmer Paris, and they made the MK VI. Now Selmer makes an array of models. I would recommend a Super Action 80 Series III, but there are numerous other choices. I've always liked Yanagisawa too, and the tenor with Sterling silver neck and bell really does it for me. I mean, if you are going to get some money to buy a horn, don't waste it paying collector value for what should be a horn to play every day. The Selmer Paris horns of the MK VI era were hand-built compared to today's technology. This of course made them highly variable but also produced a small amount of exceptional examples as well as a small amount of less-responsive ones. The great majority were good horns to varying degrees. So, your chances of scoring a great MK VI tenor strictly by luck are not odds that I would put any money on. Even if you did, you're still dealing with a very old instrument that is going to drain your wallet at every turn; replacement necks are basically not available, shops jack up the price for everything associated with maintaining/repairing one, replacement clamp collars (neck receiver) and other parts are not available. I bought my last MK VI tenor in 1998, and I mean 'the last'. Nothing wrong with the horn, but I just turned 68, so who knows for how long I'll need a pro-grade sax, or any sax for that matter? But you didn't grow up with one, like I said, so really you should have no need for one. Particularly to get through hi-school and college with. Practically all saxophones in these environments suffer serious damage - this is why they sell 'student models' - less money is being risked in the hands of children.
Bottom line, if you want a better sax to play with, fine, but you probably should not even consider dragging a rare, expensive MK VI through hi-school and college.