Apparently the previous owner spilled some soda or something under the passenger seat a while ago... There's a couple pinholes through the metal but most of it is surface rust...I figure I'll give it all a good scraping down, apply some silicone to the holes, throw some rust converter on the remaining rust and then spray some paint over it. Hopefully it doesn't spread much. Being in MA, the salt in the winters has been harsh enough on the stang's body.