NGK's are the best plugs out there, that being said, cheap copper plugs all the way.
I have ran iridium's, platinum and copper plugs in my truck, no difference between the plugs in either performance or MPG.

 

I talked to 3 shops today and all denso 5305 recommended. Any input I think that's the number I have it written down but its not on hand.

 

LOL... like said, I ask 10 people I will get 10 different answers. Copy and paste for motor oil and tires lol.
I think for the $1.99 I will rock the Bosch Platinum. I've run either Bosch or NGK in every car and never had an issue with either, including some pretty high performance cars. I've put the +4 plugs in and never saw a difference in the past, and the truck currently has them, but I think for the price the regular platinum should be good. I honestly just want to look at each of the old ones a bit further, so figure swap them out while I'm there.
Thanks all!

 

i'll throw my 2cents in here... bosch plugs have never failed me, but on a dyno i have seen +4's loose power in a v-8 application (ford)

"x brand has always made good plugs" is poor advice. companies do alter manufacturing processes over time . Around 2003-5 champion switched manufacturing processes and their plugs at that time were of a lower quality... i mean visually you could tell by looking at the threads on the plug- they practically looked serrated!

some champion some ngk most autolite plugs i have seen have very poor threading, poor/cheap threading is good way to have your plugs seize and require helicoiling your heads.

i've personally seen three champion plugs out of two different motors and an entire set of autolites (in a 911) that came out with the head threads.

my advice is simple...
1. check the threads for smoothness
2. don't use platinum in a turbo motor unless rec'd by manuf.
3. anti-seize the threads and di-electric grease the plug boot inner
4. check gap before installing

The "plug's electrode" is where the spark originates from the ground is the hook part that you set the gap on- with plugs like NGK race iridiums one of the things you are paying for is reducing the size of the ground making it more of a 'point' and exposing more of the spark which in theory gives faster burn and more power/efficiancy. I can't speak to other tech like plugs with built in capacitors but i can say reducing ground overhang is an age old racing trick from before there were so many different plugs and it's still used today in 'formula' racing where plug type is deliniated unless rules otherwise specify you may not modify them.

If you're on a budget, want to do something to 'enhance' your car you can file down the plug ground to expose more spark.

also, when in doubt 1.99 bosch plugs are a safe bet.

 

I ran a ton of different plugs in my other car. Never been able to notice much of a difference as long as I ran the correct heat range, proper gap and a good quality plug. Bosch, NGK, Denso and champion are all good quality.

With that being said I do run Bosch Platin in the Audi (28lbs boost), Denso platinum in her Honda and will install Bosch platinum in the Rover.