Hi there - few points from me:
1. I have the carbon seats and whilst they look like they should be quite hard are, for me, more supportive and comfortable than the leather. One of my favourite 'upgrades'
2. I've never used the full weather gear but don't regret ordering it - you never know when you might need it and then you'll likely really need it! I, like others, use a half hood - the Caterham one with zips to allow vertical space are brilliant.
3. don't know if you mentioned brakes - I was going to get the upgraded ones but glad I didn't - the standard ones are fine with upgraded pads and much cheaper to replace pads etc.
4. exhaust nose - I've never seen any problems with the 420 and the side exit re noise - I believe the 620 is marginal hence rear exit normally. I really wouldn't worry about it.
Oh and re the springs - I was thinking of race but glad I didn't - the standard sports springs are plenty hard for track and pretty hard on road - I think race wouldn't be acceptable on the road.
Last bit of advice from me is get the programmable shift lights - the single change up light as standard isn't much use and the rev counter is a little damped too meaning it's quite easy to hit the limiter in low gears. However with change up lights in your peripheral vision it is much easier to get the max from the engine without mistakes. I had mine fitted recently and makes a big difference for me.
"but Donington is a bit nearer and most definitely a favourite, they also have pretty tough drive-by limits"
I always laugh at the imposition of noise limits at Donington, given when the planes go over you have to stop talking as the noise is so loud you can't hear anyone even if they are right next to you.
We had a few 420s at Donington at the club track day last monday, don't think any of them had any noise issues there. In fact, unlike Bedford I've not seen any Caterhams have an issue at Donington when I;ve been there
Midlife crisis begun....
Thanks Andy, yes, agreed on the ridiculousness of Donington's limits. Sadly the circuit management seem to face the ire of punters but not a lot they can do about it when the local council calls the tune.
Useful feedback on 420s being OK :)
I've just got my 420R registered and the standard exhaust was perfectly fine on the IVA (Caterham do not bother fitting the rear exhaust these days for the IVA). The Tillet carbon seats with padding are super comfortable even after 1.5hrs of mixed road driving.
I'm still waiting for my half hood from CC despite the kit being delivered in March, however the full hood is not terrible to put up and is fine to drive in once you are inside (although getting in and out does require a little more flexibility). It is also good if you have to trailer the car anywhere or leave it out overnight.
The Caterham branded ACES shift lights work for me as I've never seen the single shift light illuminate, apparently it does at maximum revs but I've got my eyes firmly on the road at that point and the limiter would kick in before I could react.
My aces shift lights have been on since new, factory fitted. The green light comes on below 2500. The first yellow at 5000 and the rest at about 500 intervals.
I find the first one really useful on the road. Changing up at 5000 gets you along at a fair old rate without attracting attention or being silly. Especially useful if dark.
On track I don’t find them so good actually because if you go close to the limit and change up, some of the lights stay on, so ‘corner of the eye’ viewing is useless, there’s always a light or two on!
DRE shift light are much better and a fraction of the price too
It was my car Caterham supplied the rear exit for (IVA July 2020). They don't normally do it, because in 95% of cases its not needed, but since the IVA was early post lockdown a true belt and braces approach was taken. Ironically the parts supplied didn't fit my car, and there wasn't time available to resolve that, so the car was tested (and passed) with the side exit.
My detailed build blog