i just switched to the Bosch Fusion IR (Iridium). They seem like they're the BOMB! BUT!!!!!!!! 1 problem i didn't plan on having was...... during taking the 8 plug WIRES off, on 4 of them, the plug end's internal piece that grabs onto the nipple of the spark plug... ripped out! Cutting off any kind of electrical connection that wire would have made. I even tried to fix the wires, then re-install them. BUT my truck could hardly even run at all. Good thing i did the plug change in front of Advanced Auto Parts, because i HAD to go right back in and pick up a set of new plug wires and put them on before i could even leave. Good thing was, it made me swap the wires at the same time, and now it runs like it was 5 years younger. Just sucked b/c I was short on time and money that day and ended up spending both! Sorry for writing a book, but this did happen to me and i was pissed. So just, giving you the heads up!
But in all, i'm for sure happy with the plug change. I swapped from the AC Delco Iridium to the Bosch Fusion IR. I'm glad I did too. I'm sure that a new set of wires helps them out too though. Advanced auto carried the Fusion IR's for $7.98 and the wire set was like $36.00 for the cheapy but they seem fine for now.