The offered $400. Take it. The tires and impound, and his time in the pokey will ALL be found, by a court, to have been based on probable cause and reasonable reliance on the drug test.
No way the system is going to accept a penalty for this. Heck, guys have been jailed for YEARS on prosecutorial misconduct, and all they get in recovery is an "Oops."
They should at least waive the impound fee and get him some used tires for his truck........................