What is your trim level? I think that only certain Legends come with stock 6x9's in the back. They should accept 6.5's easily but if you must have the 6x9's find somebody that is parting out a LS Legend with the 6x9's in the back and ask them for the plastic containers that hold the rear speakers in. This is a plastic basket for the back deck that adapts the 6x9 speakers to fit in a 6.5 hole. Either that or make custom boxes in the back for them.