Does anyone know about problems with the alignment of a Cayenne S 2004. I change the tires 8 months ago and I have to change again.

 

The alignment on a lot of Porsche models has to be really dialed in well of tire wear can be affected greatly. You said 8 months but didn't say how many miles you put on it in that time. I've seen aggressive drivers get only 16K miles out of a set of very high-preformance (soft compound) tires, even when the alignment was perfect.