Yeh off the top of my head.... just remember it is a van so will be noisier than a car you could get away with on the dash - I've put them on the underside of the top panel before and had no complaints. Just have a play around - depending on what you can be ass'd to do.

In the primastar though it should be iso on the stereo.

Just need to make sure the + - and +/- are in the right places... all straight forward enough.