Thanks for all the input everyone. I read a lot of good things (by searching) about NGK spark plugs (and wires), including the laser iridium plugs. I’m assuming the Bosch double iridium plugs would be similar? I would’ve got the NGK plugs, but wanted to use some store credit on something they had - the Bosch double iridium plugs. I’d bought the STI wires since the price was right and I’d been told those should be fine.

 

Geez mollusc, I used to like you. Sounds like an emotional reaction.

My truck's performance with Champion 7070s refutes your statement. Copper Champions won't last long in a DII, but the double-platinum 7070s specified by Land Rover perform very well even if they're not what the "cool kids" use.

 

Only brand I ever used that gave me issues in all my years of wrenching = older Bosch Platinum/Double Platinum/X2/X4 design plugs. They have since re-designed their line of spark plugs so they're probably fine. The #1 thing that matters is they type of plug used. I hear so many people say Copper works & technically yes it does, but the BOSCH Motronic system was NOT designed for Copper Plugs. It was designed around Platinum/Double Platinum plugs. If you want the most effective spark and for it to last longer than 20K get yourself some Platinum plugs.

Also I've NEVER driven a LR V8 like Mrs. Daisy. I was taught very early on the LR V8 be it a 3.5/3.9/4.0/4.2/4.6L all run rich and develop carbon deposits very easily and quickly if driven like an old lady. LR Tech's way to test especially on D2's was to take it on the service loop and leave it in 1st gear and let it bounce off the rev limiter. If you looked up in your rear view mirror and you couldn't see behind you = Engine had massive carbon deposits. The LR Tech would then tell the Service Advisor who would inform the customer of the LR Fuel Treatment to clean out the carbon deposits. After that reset the Adaptive Settings, and drive it like ya stole it.

Most used LR's I've got my hands on suffered from that and I either did an Italian Tune Up on the test drive (LR Method lol) or I'd do a seafoam treatment. I've also run 87 octane in my 96-99 D1's and 99-04 D2's and I still drive em to the rev limiter. 89-95 stuff with a 14CUX and a dizzy I run 87/89 and then toss in an octane booster.

 

Here's something else to think about plugs. Some of us (i.e. me) like to "read" and change our plugs from time to time, so we don't need super long lasting plugs. Especially if we only put on 5K or less miles per year. Iridium are made to last "forever" and never be seen again after installation. So, the heat range, matched to driving style, is actually more important than the plug materials or brand, in my case.