What is the difference between the NGK TR55GP and the PZTR5A-15?
The PZTR5A-15 is a Premium Laser Plug according to their website and says its the OE plug.
Any differences?

 

A Plug is pretty much a plug. As long as it is platinum tipped and correct heat range you are in good shape. I know there is a lot of hype out there about plugs but most of it is just that, hype and money is better spent elsewhere. I have had real good luck last several years with Autolite Platinum tipped plugs in several vehicals for what it is worth....

 

i use ngk tr55 plugs. gapped at 50. when i went to nitrous i went to a tr6 plug gapped at 35.