i'm seriously considering an a4 2.0t quattro and this is the first i've ever delved into audis. does the avant have a smaller back seat than the sedan? I know I want s-line, 6 speed, if the nav system is any good, that too. If it's trash like my bimmers nav, i'll go for aftermarket. what are some other must haves? are heated seats only available with premium? what does the cold package include (if heated seats are part of another package) ?

thanks!
Rob