I see from KevinM's web site he is using iridium spark plugs. Kevin, (or anyone else with experience with iridium plugs) what advantages (and disadvantages) are there to using this type of plug and will you notice any type of performance gain? Are they just a "plug and play" type swap-out or is there anything that I should know? Reason I ask is I had 2 brand new DENSO Iridium plugs given to me for my V-Force and I was wondering if I should throw them in. Thanks.