To the OP, I think the listings on eBay are by PW Motorsport? If so, I have just bought a set of 19" BBS CH's from them and I can tell you that Phillip (main man) is a pleasure to deal with. My wheels came from Germany in 4 days and they're being fitted later today!
To help you out (possibly). I have experienced the difference between 215/40/18 Dunlop Sport Maxx and 235/35/19 Michelin Pilot Sport 2 in my R32. I found there was much more grip with the latter. Once the PS2's had a hundred miles or so on them, I can honestly say I was amazed by how much grip they provided. I’m not sure whether this was due to the extra half inch of road contact, the lower profile, the tyre design, a lighter alloy or a combination of all four but the cornering capability rose significantly. I could carry at least 5 mph more speed through corners before loss of traction occurred which is astonishing in my opinion. The ride was a little firmer but that’s a good thing as there was more information coming through the steering wheel. Road noise was up ever so slightly but it wasn't intrusive.
Hope that helps, here’s a few pics from Friday (they look even better in person, you won’t regret it).


