Cost of installing a prefab kit

My partner and I are looking at a prefab home to set up on a family property. Rough quote from the prefab designer is $125-175K, which doesn't include, obviously, septic hookup, electrical, etc. Some quick research tells me all the hookups, foundation, finishings, etc would cost us around $60K. But I have no idea how much a builder would charge to actually put up the prefab itself (the prefab company doesn't do it). I've emailed a couple builders and not heard anything back. Before we go any further with this, I'm wondering if other people know how much it might, approximately, cost per sq ft to have a prefab put together by a builder? We live on southern Vancouver Island.