Hi all! I'm planning on upgrading to a 2006 S4 in September. Most likely I'll be using Audi's premier purchase to finance. The website lets you calculate a rough estimate on payments, based on full retail. At the end of the model year, with the RS4 about to be released in the states, I'll surely be able to pick up one around invoice. My question is, does anyone know exactly how payments on this purchase plan are calculated? I'd like to get the formula and plug it into excel so I can estimate my payments.