The idea is that you're not supposed to need to upgrade that stuff for the VE conversion, however results will vary because these cars are edging on 30 years old and you may have to replace stuff accordingly (I have also found a lot also comes down to the quality of the bleed job). If it were me I'd just do the VE calipers first and then go from there, no point in buying a whole bunch of extra stuff and pulling it to pieces if you don't need to. Is probably going to be a lot easier if you get an all inclusive kit specifically for this with all the hoses, rotors, and components included and then trouble shoot with the shop if there's issues.
As for performance, if each one is done properly then they likely will be both more than adequate to the point where you wouldn't be able to tell a real difference between them unless you were circuit racing or something stupid.