I've got the Grp N mounts. They're not bad. Between the Dunlop SP5000s, STi mounts, eibach springs, and Ver 5 struts, there's quite a bit of road noise on rough roads - concrete or stuff with tar and gravel that gets pounded in. On fresh asphault it's smooth and quiet.
I routinely drive 160 mile day trips (between my place and my parents, or my place and my gf's, twice a week or more now) and it's not abusive. It rides a lot firmer, less like a Caddy anymore, but it's not bad.
If you have to drive clients/customers around, it might be a good idea to refrain from doing the upgrade.