Difference variety and variation:
Variation is commonly used to describe the different classes or options in a certain product. For instance, the BMW 7 series model line ups have different variations according to the cc of the engines and the different specifications in terms of luxury like the 728, 735, 735li, 740i, 740 LWB, 740d and the lists goes on.
Variety on the other hand refers to an item which is similar in nature but of different origins for example there's a variety of car to choose from at our car showroom form most of the renowned car makers like Bentley, Mercedes, Volvo, Proton, BMW and many more.