I am surprised about the low mileage on those newer TDIs.
Wife has a 99.5 TDI that gets 50 mpg in town or highway. It's getting up there in mileage (172K) but we'll keep it till it pukes.
The lower MPG's on the newer TDi(s) are a direct result of tuning for "peppier" performance to sell more cars as well as requirements for fewer emissions then the older motors. Those are always the trade-offs, no way around it... NOT that there is anything wrong with the better MPG of the older motors!!!