Canada pretends to be more European than US, but when it's about speed limit, they strongly deny it (btw, E.U. countries got 130 km/h [that's 80 MPH] speed limit on freeways and many four lane highways)...
As long as they are the law, it's better to let them do the search and let you go, than asking for a warrant and getting a real hard time from the blue boys...
A cube van will give you more room in the back, but it'll drain your wallet when it's about fuel. Also you might be pulled over pretty often since some cube van drivers are hauling heavier freight that they were supposed to...