What's it weigh?
The Exotic carbon fibre front derailleur clamp weighs 5g for the 34.9mm size. The weight is extremely competitive and around 10g less than the equivalent KCNC aluminium clamp. Indeed, the Exotic clamp weighs less than the Parlee Front Derailleur Clamp (7.5g) and around the same as the MCFK clamp (~6g).
What's it cost?
The best thing about this clamp is the low cost - under AUD$20 delivered from CarbonCycles. Most other carbon fibre clamps in this weight range are around $80-100.
Yes, the clamp needs a slight amount of material removed where the clamp band comes together to ensure that it clamps up properly. See the image below: