Outer Limits 4x4 Board

i have 105 series 4.5 petrol on gas i have just bought a set of top gun leads and they only come in 5 mm same as standard,and a set of iridium plugs is that the best way to go as i want to do it this weekend.
please help
cheers mick

I prefer the factory leads on this engine compared to aftermarket.

Bosch have a special on thier platinum plugs at the moment, dirt cheap.