Pajero Owners Club of South Africa

i took my 3.5 v6 to Powerflow for some work on the exhaust and they told me that they suspect the manifold gasket on the one side is leaking. they tell me that it can make a massive diference in the power output of the engine and thus consumption. is this correct? what is an easy fix or shouldmi have it replaced?

Just replace it. It is like a hole in the exhaust....