What's best chassis mod?

The best chassis mod may be to quit making it heavier with cages etc... if not required for the type of racing you plan. Which begs the obvious question, what do you plan to do with the car?

the car is a street strip car, its not a daily driver, it comes out for some midnight playtime when we get decent weather, and strip time.

in the uk, any car less than 12 second needs a cage, so im kinda stuck with that one.