I finally got around to putting in the Denso Iridiums I bought a while back (thanks to Rory for the plug spanner ), the fronts were handy but the rears were a huge pain in the ass. After removing the manifold and disconnecting half of the engine ancillaries, I got stuck in. The plugs were welded into the block, I had to go at them with the WD40 and a load of elbow grease, I pretty much made sh!te of the plug spanner in the process. The Denso Platinums I removed had about 45k kms on them and I reckon they had another 10-15k of life left. I've noticed since putting in the Iridiums that the engine revs a lot easier, apart from that, the difference @ relatively low revs is negligable. I've yet to the car out for a proper run but I reckon that they should liven things up a nicely at the top end of the tacho.
I've never had to replace the rear plugs on the V6 before, it was something I had wanted to do for a long time more so to understand the process than anything else. Heres a few pics:
CJ