Just back from the UK and a couple of days at the Goodwood Festival of Speed. A side note, if anyone is considering attending in the future I could not recommend it highly enough. Standing next to Hans Stuck, Nick Mason, Jacky Ickx with numerous Le Mans Porsche 917's, Auto Union's, Mercedes SLR 300 (#658) etc is almost indescribable, and there are just so many like this...
Anyway, back to the point. I had the chance to take a few photo's and talk to Dan (the person who engineered the 620R), and ask a few questions.
Photo's I took are here -
http://s1209.photobucket.com/user/jfgw/library/Caterham at Goodwood Festival of Speed%2 02013?sort=2&page=1
I also have tons of others from the event which I will put in another album and create a separate thread.
Info I gathered:
The 620R is in an S3 chassis, not an SV.
Has only been engineered so far for a RHD chassis - they have not done a LHD one so far. There are some significant challenges with pipework routing which would need some re-engineering.
Crank in the 2.0 Duratec is stock but pistons and rods are forged.
Compression ratio has been lowered to 9.5:1 by using a different head gasket.
Supercharger is Rotrex - believed to be available from them separately, but whole kit is not currently available separately from the entire car.
They would not remove the nose cone, but there is a water-based intercooler as well as an oil cooler and the water radiator.
The revised vents in the nose greatly aid cooling and so far (based on the race series) they have had no overheating issues. It has been mid to high 80s in the UK recently too.
ECU is an MBE unit - different than the R500, mapped for 94/95 RON
There may be other info I gathered but can't remember - let me know if you have more questions.