downpipe and up pipe

whats a downpipe and uppipe. thanks

for downpipes i cant put it better than sluttypatton did in the forced induction forum. he said-
"One should aim for as little restriction as possible in a turbocharged exhaust system, since the turbocharger partly relies on the pressure differential between the manifold and the downpipe in order to run. Therefor a greater pressure differential will increase the power to the turbine, and make for a generally more responsive turbocharger."