Why?

 

Peter advanced timing will increase plug temps it's recommend to run a colder plug once your ecu has had a tune put through it for stock cars keep the standard plugs

 

Didn't know you have another tune it yours.:-)

 

Snerk!
I bow at the humble truth of Seans comment...

 

Highly recommend it Peter these engines absolutely love to rev and respond very well with the correct mods

 

I'm in need of a little guidance on my 2014 XKR.Could somebody please post pics of what I need to unscrew to get to the coils and sparks plugs?I had a mechanic change out my spark plugs last time in an emergency cause I had it towed to a random shop when my Jag completely died after I kept driving it with 1 faulty spark plug,and I had him put cheap 1s in that he had available.I wanna do it myself this time and replace those champion platinum spark plugs i had the mechanic put in for me and change them out myself and replace them with iridium NGK's that i bought.