RE: engine generated interferance on 2.4
Surely you have one of the major auto parts chain stores somewhere near you, you can get genuine NGK plugs from one of them for about $3 and not pay shipping, they will probably have to order it and it might take a couple of days, but you still won't get stuck paying for shipping! I ordered NGK plugs from Auto Zone and had them 2 days later for around $3 or $4 each.