Don't bring a truck or guns with you. Change some dollars for euros. Remember that the US has an insane tax system that follows you abroad and you still have to file taxes in the US in addition to the country you live in.
yes, be very careful of PFICs. I can't use any of Japan's versions of ISA/IRA because they all end up being PFICs which are awful to deal with on the US and more than destroy any tax advantage of putting money in them.