I was looking at two W203 saloon cars at the time.
One was a 2006 Classic SE, the other a 2005 Sport. I don't remember if the Sport had the Avangarde logo.
The additional options were automatic transmission and metallic paint (one was Obsidian Black, the other Silver).
In terms of spec, the Classic SE rode higher and had identical 16" wheels all around. The Sport was lowered and had 17" wheels in a staggered setup (the rear wheels were wider than the front ones).
The internal trim on the Classic SE was wood-effect (which I quite liked), while the Sport had brushed aluminium strips (which I liked less).
I don't remember the Sport as having additional spoilers, but I am not sure.
Also, I later saw a 2006 Avangarde car in the street, that had drilled front brake discs, which my Classic SE did not have. I don't think the 2005 Sport that I was looking at had drilled discs. So the drilled front discs might be part of an additional package.