MC Transformer or phono stage - help anyone?

I am seeking the sage advice of all the vinyl experts. I have a Benz ruby 2 on an Audiomeca romance arm and turntable. I run it through the moving coil section of my Musical Fidelity Nuvista M3 integrated. The cartridge is medium output (.4 mV) and while I am happy with the sound I suspect the phono stage is the weak link of my system. I notice the bass to be a bit weak particulary lower notes. Does anyone have comments on what sort of improvement adding in either a good moving coil phono stage or transformer would have (little or large). If so which would you recommend (stage or transformer and brand)? I have tried to read up on this but still end up quite uncertain. My price range is uncertain - I would say what would I have to spend to see a reasonable difference. I would hope somewhere between 1-2,000 but less would not be bad. Options I wondered about were the Benz stage or the 47 labs phono cube. The rest of my system by the way is listed. The room is a large one (18 X 40 with cathedral ceilings and I listen to mostly classical and jazz, but some rock as well. Thanks in advance for taking the time to read this and any help would be greatly appreciated.

Gary