I pulled the spark plugs on a 2000 xj8 vanden plas. They are ngk iridiums bk r5etx-11. Looks like it could be the original one. Car has 155k miles. I looked on Rockauto. Between the 4 types( copper, Platinum, Double platinum, and iridium), what do you folks use or recommend. Each one having its own benefits of course.
Highest priced ones are iridium ones: Autolite-$4.55; Bosch-5.05 and Denso $7.04.

Iridiums having a higher melting point, conductivity, strength than platinum for max. durabililty and lifespan.

Platinum has longer life than copper and less risk of misfire which can cause cat. converter damage.
Copper-having higher conductivity than platinum but shorter lifespan.

Tough decision huh? LOL!!!

 

I like NGKs simply because I've never had a bad one. I would go with the iridiums simply because it isn't the easiest job to do on the car. Why do it more often then you need to.

 

My first choice would be NGK plats or double plats, then DENSO of the same.

Never had a problem with either.

I consider changing plugs on the XJR to be an easy job since they are up top. Try changing plugs on cars where you have to reach in through the fenderwell

 

I never said it was hard just I've had much easier and it is quite time consuming as all the plastic and rubber bits by this point are not spring chickens. Why do it more often then you need to. Yes it isn't a lot of fun to do on a boxer that doesn't have room in there.

 

Don't know about that.

The only engine I have had experience with where it would be easier would be an Alfa DOHC-4 where the plugs just sit fully exposed in the middle between the cam covers.

On a Jaguar V8, it is only a coil cover plate with six screws and the two screws on each of the coils. I don't bother with undoing the wires.

On a 70's Firebird it was jack up the front end, reach blind with universal and double extensions over the tire, under the inner fenderwell lip between the AC compressor frame and the exhaust manifold. A few cuts from the fenderwell lip was par for the course. Rinse, lather, repeat every 8-12K on the street, or more frequently if a street racer.