If we added every fluid and every gimmick device (i.e. Tornado), our engines would be making 1000hp and have 1% friction and drivetain losses. I mean, they all claim a 10-15% improvement, so they should start adding up, right?
Just use fuel injection/system cleaner, I push the Mobil 1 oils, and change everything in a timely matter. Everything should be ok. Mine's got 163,000 miles on mine and runs great, never used any extra additives. And I've always used FRAM oil filters, but probably gonna change next time after reading stuff on here. But FRAM has done just fine for me.
But anyways, regular, timely care should keep the engine running just fine.