20V nonturbo tune-up

["Christopher Gharibo, M.D." <gharic01@mchip00.med.nyu.edu>]

Hi, what parts need replacing/adjusting if I wish to do a major tune-up on this car?  

Please advise on the kind of spark plugs that would extract the best performance from this engine.  Some friends are recommending split-fires, but I am not familiar with them.  I have also heard about platinum vs double platinum vs gold plugs, however, I am not sure which one is best for this vehicle and how often a particular type should be changed.  

Also, where do you advise I purchase the air filter, plugs, fuel filters etc.- the dealer or a parts store chain?  

Thanks.