Hey just a quick tip....
when you get your old covers off.... use a steamer on the seat foam- it will revive them. Also, when you get the leather on the seats, steam them and then go over it with a heat gun on medium/low, it will make the leather shrink down to fit the seat foam.
Careful with colorfastness of the leather though, I usually do this on import cars and their method of dying make it to where I can let the leather sit in a bathtub of cold water for an hour then do the procedure and the dye doesn't run or fade.
Peace!