300lb/ft more like, 400 would be a joke
Remaps are the best mod availiable, you will notice such a huge increase, your probably best to ask in the TDi tuning section,
Fuel consump only gets affected if you are even mroe right footed than usual (likely with more power) but most TDi's still get 35+mpg when flat out (petrol equivilant about 8mpg!) and 60 when cruising