about 1 year ago I replace my spark plugs, Went to the parts store and correct plug according to them was NGK BKR5EIX-11 , now after doing some more reasearch I am seeing that the correct plug is NGK BKR6EIX-11, Can someone please verify this, And I am wondering if the incorrect plug could have caused my 2 of my ingnition coils to fail.thanks