If you have not added any electrical loads that were not on the car when it was made no you don't. BUT, electric fans, 30 Amps; Electric Fuel pumps 20 Amps; Electric Water Pumps 6 Amps, or if you add electric windows, or a booming AMP for your stereo you would need to upgrade the wiring to handle the added load.
Even though the alternator out puts up to 160 Amps doesn't mean it is going todo so if there is no load looking for power. That is why the factory went to an alternator instead of a generator. An alternator only produces power if their is a need. Generators always out put max power rated: and can cook a battery if there is no load to consume that power being produced.