I need to change the plugs in my 99 200 Opti and was looking around for the Platinum NGKs that the manual says. In looking, I see the NGK Iridium plugs are cheaper. I thought Iridium plugs were better than platinum. Has anyone tried the Iridiums? Thanks.1999 Pantera III 1999 200 Opti 25P Tempest Minn Kota Maxxum 70 2 Pinpoint 7520s