The CU101B comes with a dartanium drag washer stock. I don't know why you would change it to another one.

To install the Calais handle you'll need a few more parts. The handle lock plate and special nut for it also. As well as 2 screws to attatch the handle. After that is all done then you need to grind the handle shaft down to make enough clearance for the handle to sit flush. For the left handed handle that part number is BNT2199. Abec 5's out of the package are fine for what you are going to do with the reel too.

The unsheilded bearings that you saw on the 50Mg are ARB. They have no sheild on them to make cleaning and re-oiling easier. Just the spool upgrade itself is good enough for that reel and the ABEC 5 bearings. The handle is a nice touch too. So have fun and don't mess up your reel too much. Also once you grind the handle shaft down the warranty is void