Stainless steel is more expensive than Aluminized steel, but you can expect a significantly longer lifespan. The two most common types of stainless steel used on automotive exhausts are 201 and 304. stainless steel is more expensive than Aluminized steel, but you can expect a significantly longer lifespan.201 is less expensive and easier to manufacture compared to 304. Although 201 can display a slight discoloration and even moderate surface rust, it will typically last much longer than Aluminized steel.
304 is more corrosion resistant than 201 and can also be polished to a chrome-like finish. 304 is significantly more expensive, so it does increase the cost of the exhaust system. Many times exhausts will feature mufflers or tips constructed of 304, with the rest of the exhaust constructed from 201. The easiest way to tell if a part is made of 201 or 304 is by testing it with a magnet. 201 stainless is magnetic, so a magnet will stick to it, while 304 is non-magnetic.
If you live in a warm and dry region Aluminized steel can give you years of trouble-free enjoyment. Upgrading to stainless steel can be a worthwhile investment. This is especially true if you live in an area that gets snow accumulations during the winter months and is routinely subjected to road salt. For that reason, the overall climate and road conditions should be one of the deciding factors as to what exhaust you select.