My car has now reached 50,000 miles, and the rear tyres actually managed to last to 50k.
I have now replaced the Std issue Potenzas on the rear this time with Michelin Primacy HP's so far the rear tyres I've used has been the original Potenzas to 20k, then dealer fitted replacement Potenzas up to 50k.
The original front Potenzas were replaced at 24,000 miles with Michelin Primacy HP's, which at 50,000 miles still have 3mm on them.
At the 50k service a front wheel bearing was found to be "grumbling" with a small amount of play found on the wheel so the bearing was replaced under warranty.
My fuel consumption remains steady still at 42mpg over the whole 50,000 miles.
Still really enjoying the IS220, spent three hours giving it a good MER polish to prepare it for the winter.