[renzop]

I would go to a shop that has high-end alignment equipment. Other than that there is nothing special about Porsche alignments. My local garage (who is very professional and honest) had no problems aligning the car and I asked for unusual (autocross) specs. Your local shop that does racing alignments for $70 is probably perfectly adequate. I would go there. If they do a crummy job you can always spend $4-500 at the dealer next week. If they do a good job you can buy a lot of beer for the $300+ you saved.

Having your car aligned every 6 months is an extreme frequency. I would like to know why. What makes you feel you need an alignment every 6 months? Does the car pull? Is the steering wheel no longer straight? Are the tires wearing unevenly?

There are only 3 reasons why you would need to do an alignment every 6 months:
1) You keep hitting curbs and/or large potholes
2) Various suspension bushings are worn and the car won't hold an alignment
3) Someone is selling you a bill of goods.