I found some pic's of the MD160 mower on the net, those are nice looking mowers but most Woods equipment usually is. I think the rule of thumb is 5 PTO hp per ft of mower so with only 19 PTO hp on your BX that would be pushing it imho. I don't know the weight of the MD160 but you would probably have to add some weight on the front. I suppose if you only need it for light pasture mowing, it would work ok on your BX but for real heavy brushcutting, it might tend to stall or bog the motor down most of the time forcing you to go pretty slow.
For years I ran a JD750 which had 19PTO hp and 4ft Landpride (540lbs). That combo worked great and only in really heavy stuff would it bog the motor down. I was told that size tractor would run a 5ft mower but I never did try it myself. If you can get the MD160for a good price, you might try it and see how it works out. If you don't like it, you probably would be able to sell it and get your money back out of it.