Hi chubbster
Yes I do indeed have the Pro Kit Eibach springs with 30mm drop. The Sportline springs have 50mm drop. I don't think the Sportline were available when I bought mine, if so I may have been tempted by the lower drop although I think they will have an even firmer ride.
When I first fitted the springs I used the standard dampers but these were 40K+ miles and basically worn out so the ride was poor. I ran it like this for about 2 months and then stripped it off and refitted with the new Gmax dampers which was an improvement, although still quite a firm ride it's a lot less bouncy

.
The Eibach Pro Kit springs are designed to be used with standard dampers. The Sportline are definatey not because with a 50mm drop you need uprated and importantly 'shortened travel' dampers.
I would not advise using your standard dampers unless you are certain they are in good condition because you're just wasting your time as you will have to strip it off again and re-do the job to fit new dampers.
You would be best waiting a bit longer until you can afford new dampers and doing the job properly 'once'.
Don't forget you will need an alignment check afterwards to set up your tracking/camber which will cost approx £40-£50 otherwise the handling will be dodgy and you will wear out your tyres very quickly.
How old are your dampers and what mileage have they done ?.
I would also consider fitting new top mounts at the front when you have it apart. They don't cost much at all.
Hope this helps you out. Please ask more questions if I haven't answered all your thoughts.
chris