What is it you hope to improve? The fact is, for all three E-Type brake systems, and “upgrade” will NOT stop the car any faster than the system the car left the factory with. ALL are more than capable, when properly maintained, of locking all 4 wheels. There are only two things that can be improved:
Pedal “feel”. The S1 Dunlop brakes work well, but pedal effort is highly non-linear. Making a maximum effort “panic” stop takes a LOT of pedal effort. The later systems reduce this effort through a combination of larger pad area, and a much greater vacuum assist. Simply swapping the stock front calipers for something like the Wilwood calipers will give the same result.
Brake “fade” can be reduced by using vented rotors. However, there are two problems here. First, I STRONGLY maintain that ANYONE who experiences brake fade when driving on the street, even with the stock Dunlop system, seriously needs to modify their driving style. Second, the rear brakes ALWAYS fade first, due to the inadequate cooling caused by their in-board location. Adding vented rotors to the rear is non-trivial.
So, my advice: If you have the stock Girling brakes used on the later 4.2s and V-12s, change NOTHING. If you have the earlier Dunlop system, and find the pedal effort a problem, install Wilwood calipers on the front, move the old front cylinders to the rear. In either case, maintain the system properly, with good quality pads, and regular bi-annual fluid changes, and you’ll have about the best brakes you can have. Anything else is a purely cosmetic change that will have no practical benefit in the real world.
If you’re driving on the track or other competition setting, any solution that does not START with adding vented rotors to the rear, and forced cooling air supply is a complete waste of time and money.