Test pipes is another word used to describe De-Cats ~ basically just pipes in place of what should be the Catalytic converters.
From the engine block as standard it should go, ...Exhaust manifolds (one either side as it's a V6) > Catalytic converters (one either side as it's a V6) > Y-pipe (two pipes going into one) > Centre section > Back box/tail pipes.
Your Zed has been modded so seems to have De-Cats (test pipes) in place of the standard Catalytic converters. Doogy types faster than me so has beaten me to the reply.