alright so im 17 and i have a 3 peice stacking craftsman box but a teacher at my school is selling a kr 560 for $600 but im going to offer him $450, anyways, i know that box has all friction sliders exept the bottom drawer that is ball bearing, is there a way to change the friction slides to ball bearing or is it worth it? i was thinking maybe the ball bearing slides from the 660 would fit?

