Add a step-up or Upgrade

Hi I really need help here. I just bought a Shelter 501 MK3 installed on a VPI Classic 2 before I had a Sumiko Evo Blue Special My concern is the I have a Mark Levinson No. 25S Phono with separate PS but is the MM version therefore do not work well with the Shelter. I have 2 options Buy a step-up transformer like the Bob Devices Sky 20 or sell the Mark levinson and get a MC Phono Stage like the Manley Chinok I have no idea what will be the best way to go the ML 25s is amazing I also dont know how much to ask for it if I sell it. Please I need some input. Thanks.
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That SUT is supposed to be excellent. Certainly the Bob's is a low risk option to try. He may even offer a trial w/ money back guarantee.
I have not heard anything better than a Herron VTPH-2. I have heard from others that it brings out the best qualities of Shelter carts.

Do you think the ML 25S is the weak link in your system? The quality of your system can only be as good as the 25S.

You make the call.
Buy the Manley or other quality tube phono, there are other sonic advantages
that a tube phono pre has over ss.