I'm looking for input on a setup for exhaust and headers for a '99 V6 tacoma. looking mainly to improve mileage (I know, boring...) How do different systems effect performance and mileage? I'd prefer a subtle and deep tone over a loud and overbearing noise.

Also, any other suggestions for cranking out some more MPG? I'm running the K&N FIPK and it nets about 2mpg. I've heard performance spark plugs help, but anything else?

Thanks in advance...