Hi again. I believe they would be the same tyre. My 19's were fitted for $296 each. The 18's are usually cheaper for the same tyre. Here is a link to another thread showing the tyres fitted new to my car. You can verify if they are the same tyre as you have been quoted.
http://www.aulro.com/afvb/d3-d4-rrs/...t2-19-a-6.html
The thread starts off about GG AT2 (the older model) but more recent posts are regarding the newer GG AT. In regards to fuel economy, this has improved since those posts, l think probably due to the engine running in.
Regards Trif.