I really don't care about gas mileage, especially with an e30 tune. I just find it hard to believe anyone can keep their foot out of an MAP tuned e30 Fiesta ST long enough to get 30 MPGs. I love my boost. I wish my car was running this week so I wouldn't have to borrow my Wife's car. Dealer slightly cross threaded one of the bolts that mounts the Cobb RMM to the transmission, and these bolts are on serious back order. I ended up having to go to boltdepot.com to order replacements for the two RMM bolts.