There's no indication that they do, but do parts from the body shop such as spoilers and carbon fiber replacements affect the handling of the car? It seems logical that they would.
32 Answers
Body parts do not affect performance. They are for "Visual Rating" only and are used to unlock DVD cover opportunities as part of sponsor contracts. Only Fine-tuning and a Dyno Run will affect performance.
2They will alternate handling performance actually. See:
Performance alterations with spoilers were first introduced in Underground 2, which allowed the player to alter rear downforce settings. Similar implementations were reintroduced in Need for Speed: Pro Street and the Shift series.
Source:
The root scoops, bumpers, rims, wide body kits and carbon fiber components all have effects. After you change a part and go to dyno run, you can see the handling score changes significantly.
Here is a nice body part tuning guide. I only find a Chinese version:
