I went to WTC in NY and the manager suggested Khumos. When I got my car they were Marshall tires which Khumo supposedly makes. Well to make a long story short I almost got to the point of postal meltdown. Steering which was crispy started with a vibration. Brought it back discovered the shop did not have a high speed balancing, I was lied to. Then the mechanic, tire changer in this case- a mechanic is a fellow who knows what he does, says the alloys are bent since the wheels while rotating had a small bounce. I told him to check the alloy minus the tire. Voila no alloy deformation! ergo the tires were the problem. I emphatically told the manager that he can shove the tires and to get me 4 new tires. I ended up with Michelin Pilot rib. Naturally he screwed up the balancing again. Frustrated I went to Silver Star, my Porsche dealer, it was there that the correct balancing was done.
Tires were expensive but they are Porsche OE tires. If they achieve optimal performance as they are supposed to get I will be happy. Superior handling, braking in both dry and wet that is all I car about. Price is not an option since everything for a Porsche is expensive so that is the way it is.