Welcome bud.
I was in the same position as you, and had pretty much spec'd up my A3 Sportback 2.0TDI S-Line S-Tronic, but just couldn't get the deal I wanted from the Audi dealers, who for the most part (but not all), were total arrogant ba5sards !!
In dropped the GTD and to be honest even though I dont own the car yet, I already feel better about the deal, having negotiated a deal vastly superior to that from Audi. Couple with that as beautiful as the A3 is, I actually think the 5 door Golf is better looking than the Sportback (i.e. doesn't look like an estate).
Don't worry about the stop start system. I've had it for the last 2 1/2 years on my DSG Scirocco, and to be honest I hardly notice it any more - you do adapt very quickly to it with DSG.