help with glowplugs
 

i am in need of some nitro plugs for my 1/18th lrp shark s18 nitro.

the nitro plugs that lrp recommends are obviously made by them,

my question is, what are the differences between plugs,

eg: r3 what does the r stand for and what does the 3 stand for,

the plugs that are recommended are standard style (whatever that means) lrp platinum / iridium plugs 35030 - 35060 available as R3 - R6

it also says always use very hot plugs for the lrp z.07s engine,

any help on plug information or even plugs i can get for this car would be great,

thankyou