Anything with the dexos spec is good. I am a pretty frequent user of the Malibu forums since I got my 2013, only recall one car with gunked up valves. I used Mobil 1 5w20 - you can get the 5 quart jug for ~25 dollars at walmart.
As for filters, I got a good deal on a bunch of motorcraft filters so I have been using those.
Probably going to run ~5k and get a uoa to check on fuel dilution, etc.