Buying 04-05 jetta gls tdi wagon

[troutzilla]

Just a few questions before purchase. I'm moving to a place about 60 miles from work that is all freeway and want to know the facts before I go to the vultures @ the dealership.
What's the true highway mileage of the tdi?

What's the best synthetic oil to run in the diesel?

Is the tiptronic a good automatic tranny or should I go with the 5 speed?

What is the basic warranty?

Will a guy 6ft 1in tall and 285lbs going to be comfortable in the Jetta? I sat in one today and it seems to be roomy but I also suffer from buyer blindness excitement disease.

What kind of power does the tdi have? I will be driving up a mountain pass every day and don't want to be one of those schmucks driving on the shoulder gettin' the finger from every jack--- that passes me.