spark plugs..ngk or nippondenso

[longassname]

The factory service manual lists 3 spark plugs for the svx.
1) NGK pfr6b-11
2) NGK pfr6g-11
3) Nippondenso pk20pr-11

Anyone know what the difference between the b and g ngk #'s?
Does anyone have an opinion on the nippondenso plug? It's a lot cheaper than the ngk plugs but i've always had good experience with ngk's.

[Earthworm]

The G plug is a special application (racing?) plug.

Our cars have the B's

When you look at the NGK plugs you will notice that there is platinum on both sides of the spark. I'm not sure if the Nippondenso's have the same. I know the Bosch plugs don't

[longassname]

Originally posted by Earthworm
The G plug is a special application (racing?) plug.

Our cars have the B's

When you look at the NGK plugs you will notice that there is platinum on both sides of the spark. I'm not sure if the Nippondenso's have the same. I know the Bosch plugs don't

Any idea what the actual difference is between the g and the b? I know b is what is supplied by subaru now if you buy straight from them but no clue why the g is listed as one of the applicable plugs in the service manual. I think the letter indicates the shape of the plug inside but if so don't know what shape the g is. As far as it being part of ngk's racing line I didn't see it on their list of racing plugs.