Modern automotive leathers are sealed with polyurethane so are impervious to conditioners. That is unless you have some of the "upgraded" finishes offered by MB.
A simple test will show if conditioners are worthwhile on your leathers. Place a small drop of water on a horizontal section of leather and observe if it darkens the surface and slowly disappears or just sits as a drop. If the former you have naked leather and should use a good proprietary cleaner and conditioner. If the later, just a damp cloth will suffice.
I would recommend Gliptone cleaner and conditioner if you like the smell of new leather. Or Buffalo if you prefer the "old leather" smell. Megs and Autoglym also do good leather cleaning/conditioning products but tend to smell of lemon or some such. You need to try for yourself