I am wondering how hard it will to swap these motors. I am swapping in a 93 Honda Civic Hatchback. I was told that it would increase my gas mileage by swapping engines. I was also told that putting a cold air intake would also help my gas mileage. Will changing the exhaust increase horsepower and possibly gas mileage? I am looking for a little more power. Right now I just want gas mileage.