They are just called Pilot XGT H4. They are, indeed, the BEST buy on the market right now, bar none, in my opinion. I seriously considered them for my C280, but decided I wanted to go a more aggresive route, and therefore bought the Pilot SX-GT (a better buy than the Pilot XGT V4 if you don't need all season capability).

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1997 Mercedes-Benz E420
Michelin Pilot XGT Z4
P225/55ZR16

1997 Mercedes-Benz C280
Michelin Pilot SX-GT
205/60VR15

1988 Mercedes-Benz 260E
Michelin Pilot HX MXV3-A
195/65HR15