Based on trying most of the popular leather care products I'd say that the product that smells the most like leather is
Griot's Garage Leather Care.
The product that works the best at cleaning and conditioning is
Leatherique.
Keeping your interior clean and protected will most likely be the best bet for maintaining that new car smell and is, imo, a better way to go than using a scented product to try and replicate it.
ymmv