My sales representative told me that my 2006 convertible was completed on 8/20/05. However, he told me that my car is sitting on a lot at the Ford factory with thousands of other mustangs awaiting quality control testing. Does anyone know if there is an issue or problem with the 2006 model?

I am pretty sure this is a preventative measure on Ford's part. They randomly select a certain fraction of the produced cars to test to make sure that there are no issues with the prodction line that are being missed. It doesn't mean that there ae problems, just that Ford is checking to make sure that there aren't.

Not uncommon for new model year for cars to sit for a bit and trickle out slowly.

This happens every year

My vert was built on 8/22 and arrived at the dealer on 9/1. Keep the faith. :-D