I don't understand why you want to lighten the car in the first place. It's not a race car and there's really no significant performance gains to be had unless you strip EVERYTHING out. Sounds to me like a recipie for dissapointment and an ugly ride.
Save your time, money and effort for better upgrades. I'd start with suspension, intake, exhaust, etc... Remember, this is a consumer economy vehicle first and foremost. You can hook it up but even if you're willing to spend more than the car is worth, you're not going to get Fast n Furious results.