I've been keeping an eye out for coilovers, and I've noticed a fair few Ebay auctions for a pair of coilovers rather than a full set. Is it worth me going for two pairs, or should I hold out for a set of four?

Springs front to rear will be different and if you have front inboard shocks they will be different to rears.

Depends on your use and expectation.

For an idea I suggest you read the post on the front page about procomp shocks

I tend to keep an eye on spring rates which seem to be the biggest difference in terms of location on the car. I wouldn't buy two lots of fronts for example, I'd be spending the same money again on a new set of springs.

I'm not considering procomp at this stage, I don't have that money available yet.

I,ve uprated springs a few times now, I would not let that stop you as they are not expensive and easy to sell on