need help with decision on a 2 seater...2005 M-B SLK 350 vs 2008 Audi TT.. mileage almost identical..price almost identical..better choice?

You would have less depreciation if you went with the 2005. However, with an older car like that, you have to start thinking about repair costs. Neither car will be cheap to maintain, but I would say the 2005 would be more likely to have some kind of mechanical failure resulting in a large repair cost. Other than that, the biggest factor will be which car do you like best? Test drive both of them and decide which one feels and looks better in your opinion.

you would be able to drive the audi in the snow just fyi.

would a mustang be a better choice? (or a more economical one?)

Audi TT= front wheel drive or 4 wheel drive depending on the model. SLK= rear wheel drive I like both cars but personally I would have to pick the SLK based on rear wheel drive ( more sports car like ), styling, value, current mercedes ownership. Both cars get great reviews, you should look up edmunds.com and read what other owners have written. Let us know which one you decide is the right one and why.

have driven both...better deal is TT, but im leaning toward the SLK. Repais for either a concern, especially for a "weekender". Thats why I wonder about a mustang...although it doesn't have the wow factor