I expect my local hobby shop to bring in what the customers want. I am a racer and I work at a shop. I don't know everything about the Baja's but I expect our shop to have what the bashers are telling us to bring in (if there is a group demand, not just one person), as well as what the racers are asking for. No shop will have every part for every car but the shop has to look at what is popular in that area and cater to that.
Not everyone will know everything about every product in the shop but a couple of people with a good product base is pretty much required.
If the pricing isn't competitive, it doesn't matter how good the servic is, and vice versa.