Alternatives to Bilstein suspension

[Green George]

I have a 40,000 mile 2000 Caterham Superlight with what appears to be original wide track Bilateins. Although they appear to be serviceable logic dictates that they are probably quite worn.
I have a 40,000 mile 2000 Caterham Superlight with what appears to be original wide track Bilateins. Although they appear to be serviceable logic dictates that they are probably quite worn.

I use the car both on road and on track days.

I am considering my options and would be interested to know what others have gone for.

As I see it I have 4 main options:

1) Get Bilstein to refurb original suspension

Upgrade to:

2) Quantum Zero - non adjustable

3) Nitron Street Series one way adjustable

4) Nitron NTR1 (I) std valving or (II) Meteor Motorsport valving

I appreciate suspension is very subjective however I want advice because I don't have bottomless pockets, so whilst I want to upgrade I don't want to get carried away.

[Green George]

Thank you all for your advice. I had a very informative chat with Simon from Meteor Motorsport and now have a much better idea about my options and the pros and cons of each one.