Brake callipers upgrade

[CTE]

I am about to buy some Granada Scorpio callipers and am told they have 60mm pistons. I have been too lazy to measure accurately the pistons on my S1 (and the car is at Guglielmi`s at the moment), but but a rough measurement would suggest they are 50mm. Can anyone confirm this either way, or if thet have fitted the above callipers to their car, have there been any issues. As far as I understand it, all S series came with the same callipers, and that they are shared with the Griffiths aswell?

Many thanks

Mark

[CTE]

Absolutely right, the standard brakes were designed for a car which weighed up to 2 tonnes fully loaded, plus a trailer, so for a tiny sports car which weighs no more than 1300kgs fully loaded the standard brakes are fine. Obviously standards and expectations have changed, but if you can lock the front wheels.....I have been generally very happy with my standard brakes, and when used with EBC Green stuff pads, have never suffered from fade, despite numerous trackdays.
I am however looking to upgrade primarily because I do a couple of airfield trackdays in my year, and my car is fitted with a BOA V6 and it`ll hit 150mph, so there are certainly a few hair pins approached at 130mph where the added stopping power would enable me to leave my braking even later!!

My car is fitted with drums at the rear, which are fine with most of the braking effort coming from the front due to weight transfer etc. There might be some benefit with fitting discs at the rear, but for me the jury is out on this one (they would look nice though).