[JayG]

What is the date code on the tires, they could be older than 5 years. Old tires can be dried out and dangerious
Also remember, you will typically go through 2 sets of rear to a set of front tires

Sumi HTR ZIII is a great street tire that is low cost and great performance
They are OK on the track

For track on street tires
Dunlop Direzza Star Spec, Bridgestone RE-71R and Hankook RS-3 are all good tires
The RE-71 do not last very long.

Personally I think Michelin are overrated, but they do have great customer service. They just did a generous warranty adjustment on some AS /3's I had on my 996 that were on teh car when I bought it. From their published warranty, because I was not the original buyer, there was no warranty. Note that most of their tires do not have any mileage warranty.

Take a look on TireRack for their testing and drink whatever kool-aid you like