Rega's T/T power supply: Is it worth the money?

I recently purchased a Rega P3-24 turntable with their Elys II cartridge. So far I have enjoyed what I have heard, but have played less than 25% of my LP's. I have read some reviews of Rega's TT PSU power supply as part of reviews of their tables. Nevertheless, at $375, it seems pricey considering the table and cartridge retail for $1200--- that is, the PS costs almost 30% of the rig. I have read that the difference with it in line range from subtle to a marked improvement in the sound. I would like input from members who own or have owned this upgrade....Also would the Project SpeedBox II work with the Rega P3-24??. Thanks, Jim