These parts should all be standard to kits:
Carbon Fiber (chassis, shock towers, etc.)
Graphite reinforced plastic parts
Ceramic balls for diffs
One way or spool for front diff
aluminum for important parts that need to be aluminum.
Tamiya should get rid of producing plastic parts and plastic shocks. They should provide graphite plastic and carbon fiber as standard in their kits. They normally release kits with mostly plastic then introduce the hop-ups months after. They make the consumer spend to much on hop-ups. It's a good marketing strategy for them but what they don't realize is; more and more RC enthusiasts are switching to other brands due to the standard parts that are included out of the box.
This is the main reason why I opted HPI over Tamiya when I went back to RCing last year. I was a loyal Tamiya owner since the late 80s before but opened my eyes to other "BETTER"