GD3 spark plugs

[chan]

Hello,

I am changing my spark plugs for my 2003 GD3.

I have purchased a set of NGK IZFR5K11. But I removed the old plugs from the engine. I discovered my car is using IZFR6K13.

Does anyone know the differences? Is it alright to use IZFR5K11 on GD3?

Should I exchange the plugs?

[chan]

Thanks claymore. I had a bit of drama with the refund at a Chadstone store. Fortunately, I got my money back after the long process.