Will there be a difference in sound or performance between the aluminized version and the stainless steel? Just trying to understand why someone would choose one over the other.

 

you are paying extra for looks and stainless might last longer

 

Aluminized is slightly thicker wall so it is theoretically quieter (hardly noticeble in real life though). SS maybe a little more durable in harsh environments (eg snow country) because there is no surface treatment that can be scraped off. Polished SS is kinda over the top for those of us who are proud to display the bottom of our cars.

To put things in perspective, the stock exhaust uses steel tubing that is not even coated so ANY of these options are an improvement over stock.