The HDs should work great for stock springs. If you don't want to lower much, you may consider installing some stock e30 m3 springs at the same time. They will lower the car about 3/4" all around, but still allow for plenty of suspension travel as well as plenty of clearance for the oil pan from the pavement.
You should be able to find a used set of e30 m3 springs on s14.net or elsewhere about about $100.
I have Bil. Sports with the e30 m3 springs and am happy with it for what it is -- a nice, subtle handling improvement with very little compromise. The HDs should work just as well for this application--maybe even better. If I had a more generous budget, I would have gone with Konis. They're better--and adjustable, although the Bilsteins are great too.