Springs... which ones?

[1Bad67]

I am replacing the SLS so I NEED rear springs. I would like to do a matched set so it handles as well as possible. I have H&R Sports on my 318is, and like them. But the wife will be driving the shark more than me. She isn't a big corner carver. It needs to be a little closer to the ground, but not so much she destroys the front spoiler. After spending several evenings reading forums, I would really like to find a set of old Dinan springs. But since that seems impossible I see two practical options. M-tech springs which can be found for around $460 to $550 online, or H&R for $260. I am afraid the H&R will be too low and too stiff. Is it worth the money to go with the M-tech?