Stainless steel will hold up better, esp. in the salt. The stock material is stainless.

I'm not sure how much longer SS would last as opposed to Aluminum

1999 Mystique LS V6 Alpine CDA-9807, Rear deck sub, Opt. TB, K&N RU-3530/MAF adaptor, custom heatshield, FSVT 17's, SCT 4-program chip, Eibach's/ST200's, Hella Fogs...