The Tech that just installed mine (and btw, it took him under an hour in my garage) said they don't replace a board - he adds a jumper board that allows (tricks?) the BMS into accepting a CCS connection as if it were a SuC plugged in. There was no exchanged boards. Therefore, there will be no change in the speed of how it supercharges.
And I must say, the Tesla adapter is pretty hefty - I was expecting a cheap plastic adapter but it easily weighs a couple of lbs. Still, way lighter than the old CHAdeMO unit (had one but sold it over a year ago because it was too slow to be useful).