Hey you should look at a Br9eu
AC Delco Iridium spark plugs.
AWSF-32C is the stock plugs
The stock plugs are best
Stock Harley plugs works as good as any.
For the stock XP Iridium spark plugs the gapping is .051, I would suggest not changing the stock spark plugs until your warranty has expired. Mazda tried giving me crap for changing mine.
stock gearing around 60 mph
the stock spark plug is the ngk ifr6l11 gapped at 39 to 43
.60 is the stock gap
Motorcraft spark plugs are a factory ford part. Any ford dealer would have them. They are also avaible at most parts stores. They should carry several brands in stock. Advanced Auto has many sizes in stock, or can get them overnight
Stock NGK plugs are the best plugs. As you raise the boost of the TT model, you can opt for the colder grade plugs but still stick with NGK.
bosch platinum 2 spark plugs come pre-gapped and given a certain stock number to all vehicles meeting that particular gap requirement.
If it is the stock engine, when you buy the plugs, the parts person can give you the gap. Many of the newer type spark plugs are pre gapped so you dont have to do anything to them. Hope this helps.