The FBI are a government agency, with some funds, and they had physical access to the devices, for some time.

The devices absolutely cannot be trusted.

Whether a person cares about trusting the FBI or not (or thinks they're happy with just flashing the firmware and replacing the harddrives) is another thing.

I think you overestimate how hard it is to add spyware to a system. Esp. if said system is not a unique design. And things like SMM makes it really easy to hide this stuff.

E.g. I would trash the computer bacause you really can not be sure what was done to it.

The FBI abilities do not end with them. There is a host of 3 letter government agencies they can (and have) gotten assistance from.

But, in this case. I seriously doubt this guy is worth trouble... Unless government knows more about him than we do (e.g. he sells stolen intel to highest bidder).