Just joined the forum but have been reading a lot. To introduce myself I recently purchased a 2004 Chili Red MCS in need of some tlc for $ 600. Powerflex control arm bushing , steering shaft , both inner and outer tie rods, powersteering pump & fan (under warranty),MSD coil & wires with new plugs and now a solid running car with 136000 miles on it .Using as a DD and took on a 2000 mile road trip to New England ,on the way back got a belt squeal that went away after a while. Once home put in garage and started checking it out , found idler pulley to be making noise . As you all can imagine found some play in balancer . This is where it started to snowball, new idler pulley , ATI balancer ,belt tensioner and Alta 17% pulley & belt are now on the way. I would like to know if anyone out there is running a standard copper plug on a similar set up and what is suggested . I don't mind changing then more often. Thanks for your patience with the long post.

 

With the supercharger reduction pulley you'll need one-step colder spark plugs ... NGK BKR7EQUP.

 

you nearly have a new car now haha. cooper plugs would be fine to run, the problem is you need to have a source for them haha, silver plugs I think are easier to get, and have better thermal and conductive properties. Brisk Silvers. Yes typically they will need changing more often than an iridium. with the 17% pulley, look for the equivalent heat range of 7 which is 1 step colder than MCS plugs. JCW plugs are also heat range 7. stock heat range is 6