one for one in maint. costs. UNLESS you abuse the turbos you can get years and years of use as evidenced by people w. over 100k on stockers. Bottom line is - cost of ownership and type of driving are 100% in the hands of the owner and not tied to one model or another.
If you (genric you) like your NA then great but I wouldn't trade my TT back for my 2+2 for anything.