Performance mods that won't affect/will hardly affect gas mileage??

[Mr.Yaris]

I'm just curious to hear from those with personal experience. I'm a performance enthusiast, but I must admit, I want to keep my gas mileage, as that is what I bought my Yaris S-Type for. I also own a 1993 Camaro Z28 w/ ~450hp, so I don't plan to modify my Yaris S-Type with anything too extreme, because as I said before, gas mileage is important. I know some mods shouldn't affect gas mileage, and could, in fact, possibly improve it. When I started modding my Camaro many years ago, the first mods were simple bolt-ons: headers, exhaust, cold air induction, etc. These mods seemed to not affect my mileage at all, and in fact, since it helped the engine breath easier and run more efficiently, my gas mileage actually IMPROVED.

So my question is, what can I do, in terms of mods, for my S-Type sedan that will improve performance but won't affect gas mileage??