NGK BKR6EYA in my 33.
$4.50 each.
Changing plugs is bonding with your beast.
When I bought the car it had in it - Autolite Double Platinum APP3924 plugs which are supposed to last 100,000 miles (160,000kms)
The guy I bought the car from reckoned you should change them every 80,000kms.
They started missfiring at idle after they had done less than 20,000kms.
Changed to NGK coppers, missfire gone, just put in my 2nd set after 10,000kms (no problems, only changed cause they had done 10,000).
No worries.