We run B6hs plugs in some of our performance VW aircooled engines w/good success.
The stock W8AC seems to start a little easier in cooler weather, hope this helps.
I've used Champion L86C plus NGK B6HS. Both seemed to perform well.
I've been looking for E3.32 but can't find it anywhere so far. I even looked at the motorcycle/snow machine dealer and they didn't stock any E3 spark plugs. I may have to order on-line.
Well, the temps here are going to be in the mid 30's for a while. My engine is only a couple weeks old. Stock everything. After reading all the posts here, I think I will go with the B6HS NGK sparker. Or would a B5HS be better?