Rectifier - I think the issues were due to earthing and if you have the 2 earth strap mod it should (fingers crossed) be OK. You are likely to get cracking of the mounting bobbins in which case the Caterham exhaust ones are much better.
My rectifier died a couple of weeks back and had the 2 earth strap mod, I had checked there was a good clean earth a month earlier. I have replaced it with a HD rectifier.
Chris what year is the chassis upgrade for, just 2012 or are 2013 included