Right, bit of a confusing one here but looking at my plugs ive taken out I have Denso PK20R11 plugs in, yet the replacements i've got are PQ20R, they look physically the same, and according to this: />http://www.denso.co.jp/ja/products/aftermarket/repair_parts/plug/cross_ref/pdf/partnumber.pdf If you search both numbers all specifications match each other, but i'm unsure if they are the correct plugs, and what, if any, can be different between the two? Cheers