I'm in need of more traction and have been recommended to go with the MT ET Street S/S but i'm seeing people complain about roughness and vibration and they are simply dangerous at freeway/highway speeds in the rain.
I have a couple hundred miles on my ET streets before tearing it down for more power. I didn't notice any roughness or issues on the highway (ran up to 90mph heading to the track). Now that said, messing around on the street, curves and corners, you will feel the rear sway if going at a decent speed. Maybe it's all the years of solid axles, but it didn't bother me, so I didn't find it too much of a problem to bring it back in line. At the track, I was disappointed as I only saw a very small improvement going to these from the F1 that was on the car before. I still had traction issues in first and second.
I'm looking at the 888 or RE-11 once the car is done. If I'm going to need to peddle it with a DR, I might as well run a tire I can push in corners too. At this point I would say go with a good all around street tire instead of the ET Street, the concessions outweigh the benefits.