I've got a MY2003 WRX wagon and (if I'm staying out of boost) I can get around 23-24 city and 28-29 freeway. When I keep it at low boost it doesn't change much. Your gas mileage all depends on your driving characteristic. And yes, both the WRX and STi require premium fuel for their engines.
P.S. I believe there was a whole 'nother thread on this MPG subject. Try doin a search for it and that will probably render you a lot more help.

 

I have an LGT which has essentially the same engine as the STi, I was getting about 16mpg around town during the winter and 25ish on the freeway. Now that spring has hit, I'll get 19 around town (advertised) and about 27-28 freeway (if I stay off boost and coast a lot).

 

2002 WRX Wagon, 5speed
Best mileage ever... 26mpg tank average got it maybe twice...Mostly freeway, around 65-75mph

Worst... 18mpg.. mixed driving with quick starts

Average... 22-23 mpg... 1/3 city, 2/3 highway, normal driving.

Yes, you need to run 91 or higher in any turbo subaru.

I had no illusion about wrx fuel mileage when I bought the car, because the salesman said I'd probably get 20 mpg.

 

Yep, you'll be paying about the same for fuel. If you want an economic car, the best you can do with subaru is a 2.5rs.... otherwise a civic will have to do =).

 

With my '02 WRX Wagon I get 16-18 mpg around town and 24-28 mpg on the highway.

 

wow dude I have been driving my LGT very easy and off boost lately and have been getting a good 25 MPG city (coasting has helped a lot) don't know about freeway though. On boost I was getting 17-19 in city and 23-25 on hwy.

I had to learn not to be a lead foot.


OnePremiere, I was in the same situation as you for a moment. I could have afforded a WRX but I wanted a STi. Then I figured I needed more room and bought a LGT, priced between the two.

 

Best calculated MPG I have for my 03 WRX Sedan is 27.5. I average 22 MPG. My car is stock except for K&N panel air filter, 17" wheels and 225 rubber. The wheels and tires have lowered my mpg slightly.

Scroll down the first page of this forum for "WRX/STi did the math MPGs"

 

I get around 20 in mine. A little better on the freeway, but not much. I almost always have bikes or snowboards on top of the car, which hurts freeway mileage. The best I ever acheived was 26.

Yes, you need to run high octane fuel in virtually any turbo charged engine.

 

always under 20mpg avg

rock under accelerator pedal mod ordered.

 

So many mod companies brag that their respective parts improve hp AND mileage. Take a high flow K&N air filter for example. But do they actually make THAT much of a difference? Probably not on a WRX. De-catting your car should improve both hp and mileage, though, considering that all they are are just obstructions in your intake and exhaust pipes. But I think high 20's for freeway driving is pretty darn good, considering the car aint no putt-putt vehicle. I wouldn't hope to break into the 30's, if that's what you're asking (unless you plan on havin your grandma out back pushing the whole way).

 

When I first got my 03 rex i averaged about 20-22 mpg. With stage 1 ap and a catback i average about 23 mpg strangely enuff! If i didn't have the rex though i would still have something like a 350z or G35 anyways so i just deal with the whole "gas thing"

 

17-20, lead foot, mixed freeway/town, WRX sedan 5mt.