Originally Posted by migueralliart

I believe somebody already did these calculations and the main benefit is a greater pad contact area and a wider selection of pads available, I am sure that if somebody swaps the stock calipers (1 piston) for the ones I have (GSX 2 piston) they will definitively feel the advantage , changing to a bigger brake pump might even give more grip to that additional area pad. I would be ok if you wanted to do a 60mph-0mph test and you will find that I will brake a couple of feet earlier than you, ( I know this because I tested it with a friend that had the 1 piston caliper).

Originally Posted by Myszkewicz

Piston size of the RA caliper is 60.3mm. Area is 2855.8mm
Piston size of the DSM caliper is 42.9mm. Area is 1445.5mm, and there are two of them, adding up to 2890.9mm.

The dual-piston calipers have a slight advantage over the stockers in both hydraulic power and how evenly the force is applied.

And it also answers the other question. Their area is so close, no changes will need to be made to the master cylinder.