The contractor I bought my 2000BD from said he was getting rid of it because it couldn't do what he wanted with a 5ft blade. So I got a 4ft, and
find that it handles it really well, so well that it might handle a 5ft. He didn't have any weights or loader on it, so the front was light. I only have the loader for weight, which seems to work for the 4ft blade. Kind of close on the tire tread width for a 2000, but not worth it to trade up.
Point of my rambling is this, weight distribution is something to consider in your blade selection.
Jerry
2000BD, Koyker 120