Here's a link to the EMG website. http://www.emgpickups.com/bass/mm-models.html
Basically the MMCS and MMTW are CS (ceramic and steel) pickups in a Musicman housing. So they sound similar to the 35TW and 35CS.
The main difference between the MMCS and MMTW is that the MMTW also has a stacked coil under the rear coil and it can sound similar to a humbucking Jazz pickup.
This is similar to the 35TW, but the MMTW's Two horizontal coils are spaced further apart than the 35TW because of the bigger case.
I have one bass which has an MMTW and another which has a TW and they sound very similar. Both have P series in the neck position and can do pretty reasonable MM, P, P/J, P/MM, and Jazz sounds.
But neither the MMTW or MMCS sound exactly like Musicman pickups. That said, I'm very happy with them.
If you decide to go with the EMGs, I'd recommend the MMTWs. This will give you the option to get a more single-coil sound out of either the bridge or neck, or both pickups.
All the best,