What rights do we have against 'civil-forfeiture' when pulled over by the police?

I travelled to buy a car for $6,000, and the Ex police officer who owned the car would accept cash only. he told me, "in the event you are stopped", to not admit you have any cash, and don't answer the question. They don't have the right to search you without cause. They are looking for an excuse to take it from you. California cops are well trained in this area, trained by the DOJ, run by,,,,,Eric Holder.