You can replace your BB with a cartridge as an upgrade. I usually don't bother unless there is something physically wrong with the old spindle/bearing one (what yours has.) The one your using has been around a long time and still function just fine. Maybe I just like something I can service, I dunno. But if you are set on replacing yours, you need to remove your old one. This includes the fixed cup behind the chainrings which is left hand thread (and a lot of times a real chore to remove.) You measure your spindle and get a cartridge the same length. You will need a cartridge tool to install the cartridge. It goes in from the chainring side (left hand threads) and from there gets treated like your spindle arrangement.