Help! Need help choosing "tune-up" parts.

I posted earlier about a (dealer) $115 labor charge for changing the spark plugs in my 2001 PT, and $75 for changing the power steering fluid. The shop I've been dealing with for the past 30 some years quotes $48 for the plug change, and $60 for the PS fluid. Why do I need to change the fluid I asked. To flush it, to get metal particles out because of possible damage to the pump and the rack. OK, I'll go with this. My question is...........What plug should I buy to have put in? I believe I read awhile back in this ng that the mpg and performance can be enhanced by installing a particular brand of plug. What brand of plug would that be? Any other suggestions for having something done in this "tune-up" that might improve mpg/performance? And no, not installing a $600+ exhaust system and other changes with a 50 year payback period.