6K should be fine.. I go between 8-10K km between change of Esso XD-3 synthetic 0w-30.. went to 15K KM with UOA done with same oil. ( cause the distributor ran out of my oil ). hasn't sheared much. ( they say it'* a lil halfway thru it'* the oil life
Tamaras car is a lil different.. hers guzzle oil for some reason and had the plenum replaced..
Wix, Purolator are both good oil filter if you can't locate K&N filter. I use the larger version oil filter PF52.. IMO I don't think there'* much you can gain from swtichin wix to K&N ( maybe lil more flow ).. Fram is no no.. it'* like the Bosch of spark plugs..
P.*. For those with oil monitor (00+).. wats the mileage and % reading before you change? Curious..