Your second oxygen sensor should be fine if it was in the exhaust stream. Long time exposure to the elements (if it was just left hanging in the rain), and using leaded fuel (and some of the aftermarket octane boosters in your fuel) is what is known to kill the sensor which was connected up post-cat.
Storm titanium 2005 Elise with carbon fiber spoiler, BWR sway bar, BOE toe links, gPan2, LidBone, sector 111 wheel studs, Grey RAC Monolite wheels with toyo R1R, Team Dynamics 1.4 with Hoosier A6/R6s, Katana2 Supercharger, ECU with 265 flash. PPE headers w/decat, CEL angle eliminator, Silent touch catback, Rear Panel Eliminator, HKS intake, V2 fuel tank, Walbro255 fuel pump. HID lights.