Why isn't it?

Four cylinder Subarus are extremely popular tow vehicles around here,
the Legacy perhaps a bit more so than the Impreza but there is little
difference between them.

Here is mine (1995 2.5 non turbo) with our club's DG1000 behind it. It
tows it very easily, including over mountains.

http://www.twitpic.com/11uvwc

Her Outback Impreza is not a 2.5L, It is either a 1.8 or 2.2L and I
think its the 1.8L. Sure I suppose it could tow her trailer, I mean,
we've all seen the picture of the smart car with the Cobra trailer
behind it. But it wouldn't tow my trailer as mine is way too heavy
for the car. Plus the point is that driving separately is not an
option. We're both going to be going wherever we are going in the
same vehicle. So why not try to bring both gliders?