MBX-5 going BL. Center diff question.

[SilentMonster]

Hello all,
I've been using this site for research for well over a year now and just now registered(bout time eh?). I will be following up with a full report after my initial question in the coming weeks. I'm converting a Mugen MBX-5 to BL LiPo. I know I need to swap out the Mugen diff for a plastic spur compatible diff. I would like to use the stock center CVD's. What would work as far as drive cup dimensions and length, or are they all the same?
Preliminary plans are MM controller, 5S MaxAmps 10Ah and NEU 1515/2.5D but more on that later. Thanks, Stephen.