Hi Rob, sorry for rudely making this my first post without introduction. However, I've been watching with great interest as you take delivery of your car.
I'll quickly say - I've been truly considering one of these for the last number of weeks (since I was first shown one by a fellow enthusiast), however the main difficulty which I would has is the point you've just made.
I'm in Dublin (Ireland that is) and we have a real problem with road quality. A spend most of my waking life in and/or around cars (particularly Lotus', Elise and so on) and can attest to the poor quality of our roads!
In an effort to find a solution for a car with as little ground clearance as the SL-C I researched a bit and I have to say I would lean towards the hydraulic front end.
This approach is used on all high-end, relatively 'streetable' cars, such as the Enzo, Carrera GT and Koenigsegg.
In fact in my travels I've found the manufacturer of the system that provides many components for the hydraulics fitted to the Porsche Carrera GT (and other porsches) - they may be of interest to you as you may be able to adapt something that appears quite light weight? Never used them personally, but appear very reputed in this area.
The company is KW Automotive and the system is called 'HLS'
The manufacturer is at:
KW automotive - dedicated to the automotive World
I wouldn't be that keen on your alternative solution and have so far found that eventually GRP (like many of the cars I already play with) will find that hinged pushing against the road surface pretty stressful over time - I certainly would be concerned personally, and aesthetically you're going to considerably affect the front end there.
Ok, enough rambling - please keep us posted, frankly I'm just dying to see more high resolution photos of the car as I've seen relatively few so far!
Best of luck.
Cillian.