John:

I have a 2.5 Subaru in my '87 Syncro Westy for 13 months now.
I did it for speed; my waterboxer had never let me down and
had "only" 150,000 miles.  But I wanted to go faster over the
passes in Colorado.

I do.  I can drive the speed limit now almost everywhere--even
80 in W Texas against a headwind that would have held me to
50 with the waterboxer.

I pay for it with my mileage.  That section in Texas was probably
15 mpg.  Otherwise, 17-18 is typical.  On the other hand, I drove
over the passes in Colorado in very snowy weather with a max
speed of about 50 and got 22 mpg.  It all depends on how you drive.

But like a Mastercard, the smile on my face when I nudge a Saab
out of the left lane heading up to the tunnel (11,100' elevation)
is priceless!

Richard