Thanks for all the info. I'm starting my training now so I should be good to go in 2 years . Started running with an elevation training mask a few weeks ago and it seems to help a little. Can only run short burst of 2-300 yards before I need to take it off but I feel like I'm getting better at it.
As far as unit 55 , you say it's not one of the better ones, is it a bad choice??