You can do what I did, upgrade your oil filter to the larger size one, I believe the S-10 Blazer type filter is the longer one you can put on your engine and you can actually put in a FULL 5 qts of oil. I have it on my car and I love it.
I buy the big 5qt of Mobil 1 Syn 10w30 from Walmart for like 25 bucks and use the K&N oil filters, everyone has their preference on filters and oil alike. And I change it myself and its actually saves you money over time and I run my oil to 5k before changing it. And it still comes out pretty darn clear. But to me, 5k is the sweet spot for changing your oil anyways
As for additives? I really dont, I have used Duralube in the past on my old GT, but it had 130k miles on it, so it needed a bit of a shot in the arm. The only thing I might recommend would be getting a magnetic drain plug for your oil pan. It will help keep any unwanted metal things from floating around your engine
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