What are the worst GT-original tracks? Why? And how do we fix them?

[Veinz]

The Tokyo Expressway tracks are the worst for me.

Only way to fix this is by replacing them with something else.

 

[MisterOne77]

2 points:
1. If it fails?
2. There's a braking point that starts while you're jumping

Did the Veyron really sound like that in GT5? Wow...