High level MC or step up?

I'd go with a step up tranny - get a quality one, like the AudioNote AN-S2. Used ones have turned up here on A'gon from time to time.

I would skip both and buy the Soundsmith Strain Gauge system. It does away with the RIAA compensation and need for step-ups. It blows the doors off any moving coil cartridge I have heard, which include the best. I have the first production unit and have been listening in disbelief for the past 5 weeks.

K&K Audio makes a very nice SUT. I believe it is $325 assembled. It can be configured for different gain levels and has the ability to allow you to swap resistors for proper cartridge loading without soldering. I used to own one and used it with a Hagerman Trumpet before I bought the K&K Audio SE phono stage.

IMO you are going about this backwards.The arm/cartridge combo is the most important aspect of an analog setup.Find the cartridge (that you can afford) that works best with your arm and proceed acordingly.

If you check recent issue of S'phile, there is a review of several SUTs and it talks about some of the issues associated with matching. IIRC, the bottom line is that matching is critical for a cart and SUT. And many LO carts are very sensitive to proper loading, so if you use an SUT, you want to make sure it is easy to swap out resistors.