There is 5 main tiers to the game, and each tier has their own color and body style. Among these tiers and colors there is different styles to help tell how advanced an oppenent's body is. The lists below will tell you a description of how they usually look in game. Tiers are used in the Championship and in the Grand Prix.
Wood: Cardboard; Wood over cardboard; All wood
Metal: Metal sheets; more refined metal; "Impenetrable" metal
Military: Scraps; Camouflage
Gold: Larger chunks; Smaller Chunks
Carbon: Unrefined carbon; Refined carbon
Weapons of the 5 tiers are the same throughout a tier, and look different from another tier