For your NA just throw some "Liqui Moly Stop tappet" in the oil when its warm. It works slowly so give it 500km. Its one of the better ones.I went magnatech. It's been good so far. Although I still get annoying ticking from time to time
BazI had a couple of bottles of 20-50 racing oil and it is renamed DOMINATOR now.Do you use the dominator oil? The red coloured stuff? How is it going for you?