At least on an EsCos, the options are severely limited with the std wheel. The Brembo 4 pots may not give any extra braking ability over the std caliper (4 pots aren't necessarily better than the std caliper), which may be do-able - difficult to say really unless someone has already tried this route.

On the EsCos, most people have to go for bigger wheels to fit bigger brakes that actually give better braking performance. Caliper clearance is a big issue on the std EsCos rims.

The EsCos rim is also going to be the 'wrong' offset for a Fiesta, which may lead to other issues.

A lot of our more technical members who *may* be able to advise are currently on their annual 'ring trip.

Have you tried the Fiesta Turbo forums where there may be more specific advice available?