you want the FR8DCX spark plugs your nissan dealer should keep them in stock and make 100% they dont give you the ngk ones as they wear out to quickly on the coil pack engines causing faults
also i might not be the oxygen sensor at fault it might be the mass air flow sensor which from nissan is £500 but you can fit ones from a different nissan model
changing cams the right way is expensive, as you will need shims that you have to get from nissan and these are different thicknesses, each cam isnt 100% the same so you need to adjust the shims
