Hey guys,

Just wondering about the spark plugs for these bikes. Has there been a preferred plug over the years?

My buddy needs to change the plug on his 350 and while we’re down at the dealer I’ll get myself a new one and a spare one for my 300.

I checked on the parts list and I have a couple choices:
SPARK PLUG (DPR7EA-9) (NGK)
SPARK PLUG (DPR8EA-9) (NGK)
SPARK PLUG (DPR9EA-9) (NGK)

SPARK PLUG (X22EPR-U9) (DENSO)
SPARK PLUG (X24EPR-U9) (DENSO)
SPARK PLUG (X27EPR-U9) (DENSO)

What’s the difference?
Thanks!