Question: upgrade pickup

hi all this is my first post so need some advice. i have a made in china sub bass i have to say well impressed for the price however i am sure i could get a better sound out of it with a better pick up so looking for suggestions. i am guessing a real mm pick up would be a vast improvement but as i am no tech head i really dont know the difference between the stock chinese sub pick up and the real deal pick up. tthanks for your help.