Finally this summer I had enough, I ordered a set of Bridgestone RE 760's after comparing them to the Continental Extreme DW 94Y XL and Michelin Pilot Super Sport 94Y I came to the conclusion that the Continental's sidewall was far too soft both from physically inspecting floor models and that the Michelin were far too expensive for any performance gain over the 760s. Please find the link that I used to do some of my primary research.
I had only two concerns moving away from runflats 1) no spare tire or room for a spare tire kit 2) reduced sidewall rigidity and hence worse turn in and responsiveness. Realistically you just need to get comfortable with the fact that neither of these issues will be fully addressed, but there are significant gains to be made in other areas.
After having put 2,000km on the clock with the RE 760s I have to say I am nothing short of impressed. They have totally improved the character of the car for the better and are a great investment, a large part of that comes from the better ride and that isn't unique to the Bridgestone's. The ride is noticeably more balanced and not overly busy; hitting a small pothole no longer rattles every panel in the car (I can't help but think switching to conventional tires would prolong the life of the suspension and bushings).
Traction both in dry and wet conditions is incredible, it has now become impossible to break the rear end free even with ESP and DSC both fully off, compared to the runflats that could be broken free with traction control off in both dry and wet conditions. The tires are a perfect match for the car as they are not ultra-sticky tires that over power the factory suspension setup which could be very problematic and destroy the natural feel of the car. The car hooks up much better off the line with no tire squeal and puts down power much better on even surfaces without the feeling that the rear end is hopping or skipping over uneven surfaces during flat-out acceleration.
I am not going to lie - I thought switching from runflats to conventional tires the drop in rotating mass would be significant enough to be noticeable, the reality is I couldn't feel a difference even if I wanted to. The truth is the difference per tire on the 225's is approximately 3lbs. Now I am sure the performance overall of the car has been impacted to some extent by a 8lbs reduction in rotating mass but I haven't been able to notice any difference.
If you are looking for your first major upgrade to your E90 or need to replace your worn runflats I wouldn't even think twice about getting RE 760s or conventional tires more generally. They will completely change the performance, ride and comfort of the car - the best money you could spend on your car.