Been there many times. The west is far superior.

Now, that said, I've had an intake (FIPK) and exhaust (Gibson) on my '01 for a couple of years. Better throttle response, far better sound, and a slight power gain, but no real difference in mileage. It mayu theoretically be slightly better, but a far bigger factor is my speed and how much I put my foot into it. I've also got a lift and 32s, and could be sucking away some of the efficiency as well.

Still worthwhile upgrades, imo.