I keep seeing posts about putting a turbo or super charger on an XB. Those of you who have, can you tell us if it was worth the cost. And how much did it affect your gas mileage, driving normally . I saw one post where the guy said it increased his mileage to about 40 mpg. I am curious to know before I invest a good chunk of change. I live in east Tenn. and my RS 2.0 gives out of breath easily on some of the hills.