my last Vehicle I ran a 19.99 mbc as it suited my 'bang for buck' project at the time.
I'm sure you know that on cars that one shouldn't just splice in an MBC and turn the knob and call it a day. That being the case, if the tune needs to be modified with an MBC already, as the OPs was, then there's no reason to put the MBC in because WGDC adjustments can be made in the tune using the stock BCS.
There are tons of reasons NOT to get an MBC, and only 2 reasons to get one -
1) Hybrid setup, which from my reading isn't a horrible idea, if not correctly. It's actually supposed to eliminate spikes pretty well since EBCS always has a bit of a spike in it due to the way PID works.