Not only does the grade of stainless matter, (304 > 409), but also the thickness. I'm not too far from you however we're in a valley as opposed to flat land. (meaning - more road salt) Had bought what claimed to be just a, "stainless steel", flex pipe, and the crap looked older than my OEM pipe in matter of months, failed in roughly 18 months, memory serving. So I purchased 304 grade via Jegs and it was holding up nearing two years, but wasn't looking good and definitely wasn't going to come anywhere close to the OEM piping.
(BTW, the aluminized steel that the shop needlessly installed to replace the perfectly fine ~16 year old OEM stainless, lasted about eight months.)