Other than aesthetically?

 

well, it keeps the fluid in the radiator but that's about it.

 

iirc there's something about pressure. you can get different PSI ones that'll fail at different pressures.

 

Raises the boiling point

 

Different caps have different pressures at which they discharge coolant into the reservoir. A higher pressure means it also raises the pressure exerted on the coolant thus raising it's boiling point. A different cap may improve the cooling efficiency in hard driving conditions but it will demand more from hoses, thermostat, and other components. This also may put more pressure on your stock head gasket where the water channels meet. This may be a serious issue, but i havn't expiramented... so i only have logic and science to back it up

My advice: keep your stock one unless you hit the track with your heavily modded Fit

 

Oh im not planning on racing my fit or anything, i was just wondering, bec I see a lot of radiator caps and stuff online, and i saw this video on drifting and the guy said that a different shift knob and radiator cap are some basic upgrades for drifters, so i says to myself, "A shift knob makes sense, bec shifting is important in all facets of racing, but how can a radiator cap help you go sideways" laff