My thought on that is the animal already died. Do not make his death be for nothing. Keep the leather seats and just explain to people that the weren't your choice and it was before you were vegan. Just don't buy any NEW shoes, belts, purses, etc. made of animal skin. I never buy new animal skin prducts EVER but I will pick up some shoes from the thrift store. Or buy from some of the awesome vegan sites like
http://mooshoes.com or
http://veganchic.com or
http://alternativeoutfitters.com or
http://ahimsafootwear.com When I became vegan I didn't get rid of all my leather. I saw it as too much wasted death and wasted money. But I did CHANGE my ways. So I wouldn't stress about the seats.