I can vouch for the Mulfab vented disc and calliper upgrade from Peter, I put them on my plus 8 and were excellent, I will do the same on the Roadster when I get the pennies
Adrian, are the 3.7 brakes not up to standard?
They are pretty good for normal road driving, but can be made to fade with lots of use if spirited driving, found this on the plus 8. The vented discs from Mulfab sorted it which are wider than the standard. Originally I split the Lockheed calipers fitting a machined plate to accommodate the disks, but later on I got a slight judder on light breaking. After lots of investigation I discovered a sticking piston on one, so as 20 years old fitted the Mulfab supplied calipers. You may be right on the 6 pots but they are quite a lot more dosh.