Spark Plug

When changing spark plug for Itsu, my motorcycle, for the first time,

Ah Chong: Which one you want? The $12 one or the $5 one?
Me: What's the difference? I never change before.
Ah Chong: $12 is racing one loh.
Me: Means can ride faster ah?
Ah Chong: Aiyah, I see your face never race one lah. I put the $5 one for you.
Me: Erm... ok loh.

Yes, that's the Ah Chong from Planet Motorcycle.