I learned about this vendor today that appears to have a great deal on Xenon air dams for early Zs.

http://www.performanceparts4less.com

Motorsport Auto sells these air dams for $200, plus at least $100 more for shipping, and then there's taxes and brokerage fees on top of that. So you're looking at ~$375 by the time you get it to your door. Performanceparts4less is selling it for $162, plus a flat rate of $75 for Canadian customers that covers shipping, taxes, and brokerage. They also have a 10% off deal right now.

NOTE: I've never ordered from them personally, and there is a note that oversized packages may incur additional charges, but it's worth looking into. If I didn't already have this airdam, I'd give them a try.

Nigel