[mykalberta]

I sympathize with your position. If I had a wife and her sister needed us to cosign, it would be very difficult to say no because of the inter family relations.

I personally would talk with your wife on this and make sure all negotiations go through here. I would definately force her to get insurance on the vehicle if she cant make the payments.

I personally would advise her that she lease instead. If she can afford it then there shouldnt be a problem.