Yeah, if you know what you're buying, what you're getting, etc. Myself, I don't know that stuff. I was glad to pay the money and know I was getting the right stuff.
I am a newb and don't have any experience or confidence inside the bike right now. I'm learning about things that are more exterior and (IMO) less scary.
If you're comfortable buying the individual jets and shims then by all means go for it!
For a newb like me though it was worth the extra dough to know I got the right stuff. It was still cheap to get the bike running stronger than ever, if you ask me.
Maybe someone here who really knows can give you a shopping list? I could look and see on my kit, I think it says on that paper what it came with. I'd have to look when I get home.