what is a good spark plug to buy?
roverconnection has
LAND ROVER plug for 60.00
NGK 20.00
bosch 70.00

 

get the bosch platinum +4 plugs or the Iridiums. they should be around $7 each.

 

Plus 4's can be bought for around $60 at the local parts store, part #4418 I believe.
How about your wires, have they ever been changed if not, they are more important the the plugs. 8 mm wires from Magnacor or STI are a great way to go,

 

I CHANGE THE WIRE AT 95K oem LAND ROVER PARTS NOW I HAVE 135K

 

yeah the OEM wires are no good. they are 7mm not 8mm.

 

Im not familiar with the HD spark plug. Id go get the other you can get them at Auto Zone for less and compare.