Hi Zo,
I'm sure there are other opinion but here is mine as a start:
Option 1
Big heavy calipers with lots of custom installation issues.
Option 2
Well proven, lightweight and most installation have been de-bugged by other, plenty of installation experience. More braking than the bug will need - ever. BTW I have fitted 944T/928S4 calipers under 15" wheels. Porsche calipers readily available at reasonable prices. My Merc Brembo 4 pots were more expensive than either of the Porsche Brembo alloy calipers. Scan all the Euro EBay sites?
Option 3
Very expensive but the ultimate performance. All custom build requiring good machining skill for the brackets etc. Details of the AP stuff is comprehensively found on here:
http://www.apracing.com/
Option 4
Only Porsche stuff sensible here as the brake bias of all front and mid-engined cars is completely wrong. The Lotus is a production car witha great deal of development time by great engineers to make low grade brake components work on their high(ish) performance car. Transfer that technology across to a bug and I bet you will be disappointed.
Clive