I guess one question that would help in figuring out if stainless is better in this application than "regular" steel is what would be the life expectancy of the "regular" product? In the "bad old days" exhaust pipes on cars rusted out eventually and had to be replaced but it doesn't seem to be as big an issue with today's vehicles. Keep in mind that I don't live up North where salt is on the road. But even down here, they'd eventually get holes in the pipe on older cars. Now you see cars with well over 100K and several years old and the exhaust system is still basically OK.
On a bike, people typically put fewer miles on the vehicle, keep it fewer years, and it's generally kept clean and indoors. So, I'm not sure that the stainless would make a huge difference. I guess it would be better with regards to not rusting as easily, and perhaps deteriorating from the inside out? All other things being equal, I guess the stainless would last longer regardless? I'm asking 'cause I don't know...it's not a rhetorical question.