Janspeed manifolds - Worth the money?

[Fred68]

With a decent set of manifolds and well designed exhaust system, the standard ZS180 would be a ZS195 or there abouts. Include a well flowing air filter housing and the std 2.5 V6 will make 200 bhp.
We don't really know how much is gained or lost by the plenum as not many have replaced them. I know of a couple of Rover 800 KV6 twin TB inlets. As to the power of those, I'm not sure.
Looking inside the plenum, it's a wonder the engine makes what it does.
It's almost like MG Rover built in HP restrictions. As to why, who knows, but I suspect it was to do with budgets.
Don't forget that in the right hands, the works 2 Liter KV6 made near 300 Bhp!!