If you want to use your H&R springs and save some money just go for Koni Yellows. You'll find them to be a nice compromise. The reason your ride is so spine jarring is because your shocks are probably bottoming out or you're nailing your bump stops. KW makes coilovers that are centered around comfort that you could also take a look at. Any coilover is going to be more forgiving than bottoming out/blown shocks though. Mine felt more compliant than my stock nonsupport suspension before they blew on me.
Active Autowerke Stage II | MMW CSv2 Exhaust | MMW Catless Headers | BC Racing BR Extreme Low Coilovers | custom adjustable rear suspension links | 19" Hyperblack CSL's | M3 style front | trim wrapped in brushed steel vinyl | Slightly smoked tail lights with clear reverse lights | factory xenons