The pirate transport is one of the transports that have the most firing power. Add a small armor upgrade in there and learn how to use the thing and traders should cause you no problems.
But please, ask money or a small part of the ennemi cargo. Make sure they stilll make profit out of their run. I know this is not really inRP but just think if you where on the trader side.
And if you want to pirate, please properly RP with the guy.I do not count the 1.ask to stop 2.ask for money 3.Let him go or blow him up if he didnt gave money as propper RP.