People get all excited when they see "RB" but an RB25 isnt anything that special and isnt that expensive. A 95 240sx is still a 95 240sx. Dont view an rb25 240sx as some diamond in the rough, it's not. Collector wise, that setup is nothing special and has no added value over it's value. Look at it like a normal car and judge it like a normal car.

If it was a super clean and good running car that i liked, id probably consider the trade. If it's rough around the edges and needs work, dont give it the benefit of the doubt or think its more valuable than it is because of the rb25, an rb25 240sx is nothing special. View it with the same scrutiny you would if you were looking at a toyota camry.

have any pictures of the car?