Thread: Which performance spark plugs to use?

Just a quick question--What are the best spark plugs to use in a Grand Prix?

Background: I went into my local auto parts store to get Bosch +4 plugs for my '94 Grand Prix. I have used those plugs in other vehicles and thought that they were supposed to provide more complete burn, better fuel mileage, etc. in any engine. However, the man at the part store told me that putting Bosch in a GM wasn't a good idea and would actually decrease performance. That sounded a little strange to me. Does anyone know if that is correct?

Thanks!

Thank you so much for the replies! I had thought that Bosch was supposed to be one of the better quality ones, so you guys saved me on that one. I also just found out that the dealership uses AC Delco. Based on that and the recommendations here I'll probably just go with the AC Delco Rapidfire plugs. Thanks again!

Good to know as I JUST purchased Bosch +4 plugs

OK--got it! I need to purchase iridium spark plugs instead of the rapid fire. I was wondering though, what is the difference between a regular spark plug and an iridium spark plug? (I know that's probably a dumb question, but I sometimes I have to learn by asking dumb questions).

What's with all the new members buying Bosch plugs lately? Was there a sale or something?

Actually, I think there was a sale lately, but I didn't get in on it. <g> I have three pre-2000 vehicles and have done all kinds of work on them over the last couple years, but only a year-and-a-half ago I had to change spark plugs for the first time in my life. (It was on a Ford E350). Really simple process, of course, but I was clueless on the different types of plugs. Anyway, I went to the local parts store and talked to the guy behind the counter about why some plugs were priced a little higher than others and about which would give the best performance. I walked out with 8 Bosch platinum +4 spark plugs and the impression that they were top-of-the-line for engine performance. That's why I went back looking for the same plugs for my Grand Prix this time. Glad to know a little better now.
Thanks everyone!