Need For Speed Undercover Hints for PlayStation 2
If you want to keep your lights on even if you're not in a chase first find your first crimanal don't kill him then hit start and hit restart. Your lights will be on even though your not in a chase
If you don't want to do every single race to finish career mode, then pause the game while in career free roam then press Jump To... Then press Next Race.
I reckon as soon as you unlock the Porsche Cayman S, you should buy it, then you can use it until you're about 80% into the game, then you might need to change cars depending on how good you're driving skills are in Need For Speed Undercover.