I'm afraid that video was not by me - it was by 'Alternaut'. He replaced the MB112 driver with a Dayton PA310-8.
I don't have a MB108 handy, but it appears to have a cab with an internal volume of about 0.9 cf - a healthy amount for an 8 inch driver. I suggest that you consider the Dayton PA200-8 for your MB108. With only 25w available, it would be safe to run plug-n-play (stock tuning) with no worries about over-excursion. It will probably sound better tuned a bit lower (60- 65 Hz). This driver (or the Eminence) will take everything the amp can give it. If you need maximum volume, I suggest the Beta 8a - it's about 3 db more sensitive than the Dayton. They Dayton will sound a little richer, but still have good note definition. The Alpha 8a will sound best sealed. It will likely need a little bass boost which will eat up some of the limited power, somewhat limiting the maximum volume. The Dayton and Beta will not really need bass boost, but will take it well. Whichever driver you get, try it near your practice volume (with the grill off) and watch that the cone excursion is not excessive (over 1/4 inch P-P).