As ever Eric has it right.

I live at 5000" MSL and spent years happily towing with a 1600cc hatchback.

Recently went over to the dark side and got a Volvo XC70. Towing the same rig
(single axle trailer with a single seater inside)The XC was purchased for it's
comfort, ability to swallow growing family and to be able to confidently visit
wilder parts of the country. (to say nothing of the hatch's 12 years and 250K km)

My observations for towing glider trailer.
You don't need more power. The 1.9TDi will tow it very well, and particularly so
at altitude where the turbocharger will compensate for much of the altitude
effect. (and yes I have driven long distance in the states)
The extra power from the 2.5l turbo on the Volvo is really nice in that it
reduces driver effort. With an auto gearbox and that much power available it is
effortless towing the 600kg glider combination. But you only win a few less gear
changes.

The big difference is in safe towing speed. The hatchback weighed ~1240kg the
XC70 weighs 1780Kg. Wheelbase on the XC70 is a good 500mm longer. 4 wheel drive
increases stability further, as do all the electronic aids. As long as the
trailers aerodynamics, and tyres and brakes are up to it...
A wayward swaying trailer and car indicates bad aerodynamics and balance more
than weight of combination.

End result - With the hatchback I was able to tow at 120km/h in still
conditions, but any wind or traffic and I had to slow to 100-110 to prevent
getting pushed around by the trailer. Every so often you would get trapped
behind slow moving traffic in the mountains, without the power to pass safely.
The heavier longer car is unperturbed by most disturbances on the trailer.

Fuel consumption - Same trip - primarily freeway, with some substantial mountain
passes included.
1600cc Hatchback - 9.5l/100km. Average speed ~95km/h
2500cc Turbo wagon - 11.5l/100km Average speed 116km/h

The main advantage the bigger car has is in acceleration, particularly for
overtaking. The places where the smaller car would have had difficulty going
faster tend to have lower speed limits so the performance difference is somewhat
neutralised.
Conversely the smaller car is much easier to manoeuvre and cheaper to run and
live with day to day.

The jetta will have advantages in the twisty bits over the SUVs - physics are
against something that weighs that much with a high centre of gravity and all
the design compromises. Tried it once, never again.

If you drive within the capabilities of your combination you will enjoy the
trip, and it does make a big difference to your average speed having to stop to
feed the beast. The TDi will really test your endurance if you want it to.



Eric Greenwell wrote:
J a c k wrote:
Allan wrote:
Not the least of
those is that you will be expected to keep up with the rest of us who
ARE driving the 5.0 L models and who are relatively unperturbed by
either stop-and-go traffic or rising terrain.

I don't think that's really an issue, as there are plenty of trucks that
will be much slower off the mark or up the hill. Not to mention people
like me, with a motorhome and a heavier trailer, that have even less
power compared to the weight. If it's a four lane highway, the faster
vehicles can pass; if it's a two lane road where it's hard to pass, pull
over when you've collected a few cars behind you so they can get on
their way.

The real concern is the stability of the car and trailer at the speeds
you will tow. Probably talking to other people already doing it the best
way to learn about that.