s6 is making 340hp 40 over regular 4.2
what is the difference??
I guess exhaust making no more than 10 extra hp's.[>:]

 

Bigger intake manifold runners, more fuel, better tuned exhaust, andi think the engine managment is tuned a little differently.

 

Would you be able to swap in the intake manifold from an S6 into a 4.2? Any cons to this or will it even fit?

 

I don't see why not, but i really don't know about that, try asking someone at audi club or call do an extensive search for it, i know people swap out RS4 intake manifolds onto S4's so i think it would be possible.

 

Better check to see whether the throttle bodies are different size before you go swapping a manifold. And the heads. If you have a larger manifold and it wasn't the restriction to begin with, then you just have a bigger volume which could slow the air charge.

I wonder whether the exhaust manifolds are improved, along with the larger diameter/reduced restriction of the rest of the system. Improvements closer to the heads tend to provide the greatest gain. The intake side of the equation is tough, unless you are addressing a specific restriction, its tough to get incremental improvement from any one change.

 

I have been looking for new exhuast manifolds with no luck. Im also curious as to if the S6 has larger exhuast manifolds. I have found new downpipes but at $1200 for the set. A bit steep..

 

Probably get a LOT more power a lot easier through the installation of a modest nitrous kit, rather than trying to retrofit/upgrade stock parts to get there. Just be mindful of the high stock compression