Mac 80mm CAI questions - 2000 GT

Just beginning performance upgrades on the 00 GT I bought a year and a half ago. I'm new at this and still learning. Anyway, the only mods I know of on the car are a K&N filter and Flowmaster exhaust. I believe everything else is stock. I bought a Mac 80mm CAI kit and am having a local shop install it, but am now starting to worry I might have problems. They are going to use the factory sensor with the kit and have told me I don't need a custom tune for this mod, until I get the headers, which is like a year away. This doesn't make sense to me, but as I said, I'm new at this. Can anybody tell me if the above is correct, or do I need to do anything else with this install...
Thanks!

more advice on mac cai needed

Thank you for the answer to my previous question. Now I have a new problem with this, my shop called me this morning to tell me the kit was in, but both the warehouses they deal with were out of the 80 mm kit and told them it's on backorder, so rather than making me wait (they know how excited I was), they ordered me the less expensive kit without the 80 mm mass air meter , and are supposed to do the install Friday morning. I'm so disappointed, am afraid this isn't worth doing, and am about to try to buy the mass air meter and have it overnited so I can bring it with me Friday morning. My first question is whether it is worth the extra money it's going to cost me to do this, and if so will another brand work with the mac kit? I'm planning to do alot of performance upgrades to this car as I get money, so I don't want to get all worked up if this isn't a big deal.

Thanks once again, guess I had that noon rum and coke for nothing!