Long story short, steer clear of this shop. In a moment of weakness when a car I had just bought died on the freeway, I had it towed to this shop because their ad in the phone book said they were experts with Z cars. I have spent a lot of time learning about and working on my car the past year since that encounter, and I can say now that my initial analysis was correct - they don't know squat and their customer service is horrible. I later learned from talking to a guy at a body shop that they apparently pay one or more tow companies to bring them cars as that is apparently the only way they can increase their customer base. I almost made the mistake of letting them work on the air delivery system and am so glad I didn't. The creepy, rude mechanic who was 'working' (if you can call it that) on my car kept revving the engine like crazy and screwing around under the hood like he was trying to ruin it. They told me the turbos were shot and would cost $2,000 to replace and said something major was wrong with the engine because it was idling too roughly. Then when I asked if they could do the work, they said it was too hard of a job for them to do. Some experts. i was actually going to let them work on the issue with the RPMs not increasing when AC is on (IAA valve assembly solenoid, I learned later) but I came to my senses and got my car out of that damned shop the first thing next morning. A year later the car runs better than ever and while I did have to replace both PCV valves, the IAA and IACV valves, and two injectors myself, rumors of the demise of the engine and turbos were greatly exaggerated. The rough idle issue was caused by the injectors being out of spec - anyone who knows anything about these cars would have done a balance test (takes about 60 seconds) and known that immediately. What a bunch of total losers! If you've read this, you can't say you haven't been warned!