I have the half leather seats, think they are called silverstone. They are grey/white on the outside and a small cloth black check in the middle. Anyway half thinking of re-colouring the leather black. How easy is this, would it look naff???
Get yourself over to Liquid Leather. Gliptone Scuffmaster is awesome stuff.
If you find a detailing site then you will be able to see loads of of recolours.
Basically you mask off the bits you dont need to cover then apply with loads of coats of the watered down solution until you build a good base colour then finish with an airbrush for a perfect finish.
As said for details and examples have a look on some detailing forums.