will installing a lift kit on my 03 outback affect the mpg, if so how much?
Yes it will, your changing the way the air flows over and around the car, how much it will change is hard to say.
Probably very little if that is all you do. Big tires won't help your mileage though.
Looking for a Used Outback in your area?
CarGurus has 33,618 nationwide Outback listings starting at $1,500.
Search Subaru Outback Questions
Subaru Outback Experts
Related Models For Sale
Used Cars For Sale