It's softened up a bit from when I first made the change, in the first few weeks it was very firm, bit of an understatement to say 'it corners like it's on rails'... everything was like being on rails.
I'm on 17" standard alloys with now 225/45/17 tyres and also replaced the ARB drop-links with Meyles.
There's no arguing it's not the most confortable and/or quiet ride I've ever had, mind you I'm pretty sure the OSF wheel bearing is on the way out.
Was it worth the expense, yes, it definitely handles and unquestionably looks better that bit lower.
How much did you manage to pick the B12 kit up for? They ain't cheap, I got the B8s from Eurocarparts eBay shop for £433. Cost nearly £900UKP in total for the B8s, springs and Eibach ARBs.
Just dawned on me why the OP managed to do his in an afternoon, by not changing the shocks he didn't have to contend with the pinch bolts on the lower fork. If they've never been replaced and are the male torx head rather than the newer female allen head bolts, it's an afternoon getting them off.
Good luck with it.