Some dealers (like the one i used to work for) use Castrol oil anyway. I would def go with a genuine oil filter (or at least one made by MANN). Plugs- currently using Bosch, have been advised to use NGK though. Air filter- go a K&N panel in mine. Would go for that, better then standard one. Leads- in my opinion there is nothing wrong with the standard ones. Remember some of the performance ones are thicker, so the channels they slot into need to be filed out to made them fit.