I was one of those who wanted to keep the EDC system on my car.
I accept that good single rate shocks can work really well (many millions of such cars prove this!) and work infinitely better than tired EDC, but I had been seduced by the dark side's dual handling personality offered by EDC (couple this with the auto/steptronic gearbox and I have multiple cars in one body to suit my mood)
The cost of new EDC shocks would be near impossible to justify - if mine fail in the future I would have to go "single rate"
Luckily, at the time I enquired, Sportsline were still doing rebuilds at about £250 a corner (they don't any more and turn down such requests).
The rebuild only replaces some of the components, such as pistons and seals, but not the valves or bodies, so totally knackered, broken or rusted through shocks greatly reduce the risk of success/long life - one reason they stopped offering the service. My original system still worked and didn't leak, but had done 100k miles - so good rebuild material.
Even so, in my case they did need to replace one of the seals after 12 months (no quibble and no charge), but other than that I have been thrilled
Burn - I presume you've been in both E31 variants. I wouldn't want to be without EDC, but many others on this forum can't wait to bin it. It is very important you experience it (working properly) first hand before spending big bucks.