Mine sounds worse as it had water sitting inside while parked for 20 years. I have to cut in some metal around the front and rear windscreen. Also needed a roof from some small tree limb hit around the sunroof. Blasting it was a proper solution because of some corrosion under the floor seam seal. I would take a look at your seat area and around the pedals. The corrosion was limited down there but always a concern.