With the VW engine at cruising you need to run at 3000rpm essentially
With the subie you can run at 2100rpm heck I just drove a new Jetta and it did 1250ish at 70mph 6.5L per 100 km
the 5 sp subie can be changed to get down to about 2700 rpm at 70mph
by changing the pinion to 3:91
and dropping the fifth gear
if not you cruise at 31-3200rpm at 70 mph