ProComp have a limited lifetime warranty, DeCarbon 2 years, both are polular. Some people swear by Bilsteins, some at them when they see the price :shock:
Get branded dampers, in a pair and you'll be fine. Even the OE ones are rather good when new, most people's are old and tired so they don't realise how good they can be.
Don't worry about the steering damper, I fitted a ags one and found the steering 'pulled' to one side as a result, the car was lifted though and without castor correction.