Lol, I think he is talking about SHO Source (SHO Shop isn't around anymore.. so it has to be it..)
But to answer your question.. it's just about what you need. SHO Source is a pretty good place to buy what you need as most of their parts are competitively priced and most of the time cheaper than if you were to buy it from a chain store.
From there, RockAuto LLC is a good place to buy/find parts (replacement).
Any performance is done with group buys or custom done (unfortunately). SHO Source does handle a lot of that.