I have the Duelers in the front and Nitto Invo's in the rear. My Dualer for some reason is noisy. I can hear the fronts but it's rock solid quiet in the rear.

Invo's aren't bad at all. 260 (or is it 240) wear so..... yeah. I figure with new rears with this kind of treadwear and fronts being a little harder, by the time I need to replace the rears, I'll get a whole set from Costco though I'm not sure which ones.

The Invo's are great in the wet and grips very well in the dry. I'm not kind to my tires at all (nor are any auto-x'ers) and the Invo's head up well. Never used Nittos but got them at a steal and really needed just a set of rears.

I'm actually thinking about replacing the whole set with ContiSportContact 2 or 3's down the line. I've had them on my 540i with M5 3.15 rear diff and they were much more quiet than Michelin's and gripped a hell of a lot better. Just make sure you don't run them in the winter; might as well drive on hockey pucks.

I'm running Yokohama YK580s from Discount Tires. Great wet road traction - especially braking and reasonably quiet & comfortable ride. Based on wear so far these look like 50,000+ mile tires. I believe Discount Tires is offering up to $200 off a set of four if you use their charge card, $100 off without.

2002 X5 3.0 274,400 miles
2004 325i 119,000 miles (also on 225/50R16 YK580s)

I am very pleased of Kumho but got them like 6 years ago and still are ok.