Used these to replace a set of OEM T001 Runflats 3 months ago and essentially transformed the car comfort-wise. However, it's obviously difficult to attribute as to how much the change is due to the change from the T001 to T005 or due to the fact that my replacement set are not runflats.
The T001 RFTs did give a sharper initiall steering response, though as cornering loads increased, the steering response move back to normal. Levels of dry grip did not live up to the sporty nature of the initial steering response, but was adequate. The T005s on the had feel a tad slower to react, but have a more linear performance when it comes to response and grip, which is good for a comfort-biased touring tire.
Driven responsibly, the T005s also behave well in the wet. They clear water thin sheets of standing water well, but of course my set should, as they are quite new. They give ample warning of impending loss of cornering grip, which is as equally as important as outright grip.
As most people have noticed, these tires are premium comfort biased tires, so it should be no surprise that comfort is their forte. They run quietly on all surfaces, and even on course surfaces, road roar appears well controlled. Even with the relatively high tire pressures Mercedes specify for what is quite a small car (36.5/33 psi), road shock absorbtion is adequate. This was where the factory fitted T001 RFTs were atrocious.
I am so far very satisfied with my purchase, and do not regret the slight premium I paid for these tires.