The problem with JLT unless they remedied it is tier use of cheap GP hose (driver's side CC). I could always smell the vapors in my ecoboost F150 as the lines were not fuel/oil rated and would allow vapor into the cab. Replaced it w/the UPR/CCS and it really does work amazing but the F150 is...
sounds like light piston slap before everything is @ 100% temp. Forged components take a bit for thermal expansion to kick in, which is why the supplement says power is restricted until oil is @ 190*. Is she queit after a nice hill run in the upper powerband? If so, carry on!
Also, rod knock...
The only bennifit to nitrogen is it's dry and will slow/inhibbit corrosion. Unless you're doing take offs and landings at 150+mph or running split rims it's pure gimmick. Saying 'it's inert properties are why' makes about as much sense as saying air is flammable, most aviation specific rims...