The issues associated with forced-induction and plugs mainly has to do with detonation (Using too hot of a plug will cause detonation, potentially damage the engine, or result in reduced timing and boost if computer-controlled) and flame-out (Too cold of a plug or a weak plug). In those cases you may not want to use platinum or iridium plugs, but something like an NGK U-groove that has a strong spark that isn't susceptible to flame-out or fouling. It's also a good idea to step down in heat range from stock when going FI or increasing boost if already FI.jessefrank said:I would have to agree with what is written above (nice write-up btw Yahooligan)..for the titan or for a light-med modified titan.
If you are supercharged/turbo'd then the plugs can make quite a difference. It's kind of like underdrive pullies...they give back power that you engine is making, but was losing. On my turbo Audi A4 using specific plugs means the difference in idle smoothness, hesitation and top end surging in the power at WOT.
It that sense the plugs can increase hp and mpg (from what you are getting currently) IF your plugs are at their change out time (100k miles)