Can someone help me out explaining the differences between a 4/2/1 and 4/1 exhaust manifold (aprt from the obvious!).
If you've replaced the standard exhaust on an XE, which one is more suitable for the XE. I understand that one design improves low/mid torque and the other improves bhp and high range torque - i think. Cant remember which way around it is tho.
Its low/mid-range torque increases that interests me more than top end BHP/torque increases.
I have a scorpion full ss system, if its relevent, and its for a mk2 GTE.
I want to get one asap but would like to hear the experience of others first and any recommendations on type and brand.