I’d consider the regular NP3 over the NP3+. The + model has superior corrosion resistance. But the + series has a softer hardness. The regular NP3 will be more resistant to abrasion and be a bit cheaper too.
Only info that I can offer is what I have read- that it is not uncommon to have issues with Fiocchi ammo in these guns. I would just stay away from it. Buy some good quality US made full power ammo, (if you can find any) run about a hundred rounds of it, before you blame the gun.