OK, I took the cover off of my 4Cyl this afternoon, and this is what I found:

#1 They are regular NGK plugs, not platinum, not v-groove.

#2 The plug was slightly carbon fouled (after 8000 miles). This say's nothing about the plugs, and everything about the fuel. I've been using 87. I think I will switch to 93.

#3 2 of the plugs have regular rubber boots on them. The other 2 have some sort of box on the boot. They are electronic looking, and have wires coming in & out of them. I have no idea what they are or what they do. I did not attempt to get at the spark plugs that are under them. My dealer is pretty good. I will walk into the shop when I have time & ask one of the mechanics about them.