the exhaust on my 740 GL non turbo has rusted itself to death. i am replacing from the catback, straight pipe after cat to second muffler and i am losing the s pipe. side out exhaust seems the way i am going. the motor has 126,000 and has yet to be started since i bought it. the engine was parked after the timing belt busted and i got it after the owner decided to buy a new car. i am confident that the motor is in good shape and because it will be my g/f daily driver she wants to keep the motor stock and efficient. so no new cam or ingition upgrades (for now.) so considering this do i have anything to gain by going to a 2.25 exhaust? my main concern is to go for the most efficient mpg volvo. thanks

benjamin