Protech - been running them on my car for quite a few years... Overall, they are a step up from the standard Bilsteins however - they do occasionally leak and have to be refurbished - nothing significant there, and the damping control / rebound whilst better than the Bilstein is nowhere near as good as supposed 'bling' dampers. Anyone who feels that decent dampers are bling in my opinion either drives on perfectly smooth tarmac, doesn't track the car or drives slowly enough that the dynamics of the Bilsteins are not exceeded. If I'd started again, I would have persevered with the Bilsteins for Longer and saved up extra for better dampers. Having driven a number of different Caterhams on Hillclimbs and Sprints when mine has been unavailable - I can verify that better dampers allow you to ride kerbs without upsetting the car, give you flexibility to dial out characteristics at the circuit due to changes in weather/ conditions - it still needs a decent base set up however, and generally gives feedback and feeling through the steering whee/ seatl on what the tyres are doing allowing you to push the boundaries further.. Nitrons were great, however the CORE digreesives fitted to Lewis Carines car as well as Ben Williams were fantastic - where in my car I'd have been really fighting to find grip/ keep it on the track, their cars were far more stable despite very similar set ups - rake, camber, caster, toe and tyre pressures.