UPGRADING HIFI - MC OHMS?

I sorta already did but - 

Yamaha P-450 (had a B&0 MMC10E cart) 

Marantz 1090 

Klipsch KG-4's

The Audio Technica VM750SH for $400 will probably be all you need. Listing all your equipment would help. MC/SUT need pretty good ancillary gear to sound their best.

Thank you jasonbourne71, and hotei - just what needed to know. Looking at the SUT + MC life, I'm going to have to do some contemplating if now is the time to dive in that zone. I did find some MC carts that are high output like Dynavector. I also found some Audio Technica MM carts that have micro ridge or shabata styluses. I'm just curious on how much better sounding an MC+SUT combination would be versus a high output MC or nice stylus MM. 

There are very good MM cartridges out there if you don’t really want to mess around with a SUT.  Ortofon or Nagaoka are good ones.

When using an mc  step up transformer (SUT) keep the connecting cable to the phono input as short as possible. This is so the cable capacitance doesn't load down the transformer's secondary winding and reduce high frequency response. On the other hand, the cable length/capacitance from the cartridge/tonearm doesn't matter with mc cartridges because of their inherently low resistance/inductance.

The Bellari step up transformer is a good budget recommendation! They can be found new on eBay. I am happy with the performance of mine!

The Marantz 1090 phono stage doesn't have enough gain for low output mc  cartridges. Those require a stepup device - an active linear amp (head amp) or a transformer with at least a 1:10 ratio. I use both: a Marcof PPA-1 battery-powered head amp and several transformers: Bellari, Denon, Quicksilver and two custom-built using vintage mic transformers.