Common practice would be to create different variants as a row in the iPart table and make the require changes. On placing the iPart into the assembly, you will be prompted to specify which variant you want to use. This can very time consuming if you have lots of different variant, but may not use all of them.
In this blog we take a look at the use of parameters when creating an iPart. The video below show you how to set this up and how it works: