H&R springs for the MS3/MS6 are nowhere near slammed. The closest to being slammed are from H&R coilovers for the MS3, unsure about the MS6 though.
The koni FSD are for stock height springs and the Koni Sports are for lowering springs.
I based my decision on Cobb telling me their springs were OK to go on stock dampers which I translated into them being suitable for thew Koni FSD's
The FSDs do seem to raise the front a small bit
There is a group buy trying to take shape on M 3 Forum for the Koni FSD's. They need ten sets and the price is going to be around $500 which is $150 less than you can get them anywhere. I'm in as I don't plan on lowering my car and will keep the stock springs. I have read good things about the FSD's except they are not suited for lowering springs. They improve the handling and ride quality vs stock dampers where as the sports may be to stiff for my taste.
For the record, neither Koni Yellow or FSDs are rated for use on lowering springs.