You can fit motors that fit any of the phantom range - T-Motor Antigravity motors are a popular choice... Although the Vision isn't meant as a hot rod sport flyer, so you might be better off trading it in for a quad frame that you can trick out yourself to your hearts desire.
You ask if it's worth it... What do you find the stock motors don't give you that you think upgrades would? The answer to that will determine if it's worth upgrading motors or actually changing your quad.