I've never driven with H&R's, but I had Eibach Pro Kit installed on my 09 G37S Coupe about a week ago. I know they're not all settled, and I haven't had an alignment done yet, but I can definitely say that on poor roads (and NY is filled with them) ride quality is reduced. It wasn't good with OEM, but it's definitely a little worse now. I do think handling and turns are a little better overall though. Like others have pointed out, I mainly did it for the looks.

Personally, I think for daily driving the H&R's would be more trouble than they're worth. Getting in and out of parking lots without scraping is already tricky enough with Eibach's.

My main concern with the Eibach's is that the front is looking much lower than the rear. It's only been a week but I have driven about 100 miles, and the rear doesn't seem to have dropped at all. It's not much different than it was before the install. I've heard Eibach's can have an uneven look, but if this is what people meant by that, then I honestly can't recommend them! Keeping my fingers crossed that it'll resolve in a few weeks, or else I'll want to take it back to the shop.

 

the only way s-techs or h&r's are bad for daily driving is if you drive like a complete moron.