Bruce - 500+HP at 1.0bar is huge.
How do you qualify that the 3.2 manifold is worth 100HP?
Were you previously using a 930 intake on the same motor?
(I know several 930s using stock intakes that are going 430-440HP to the wheels.)
512HP to the wheels is a big number that would likely not be supported by the stock pancake manifold, but by how much? That is the $34,000 question. You've built a VERY fine engine that can get you those numbers at 1.0bar.
I think in order to accurately and directly answer the question posed we need to know what the expectations are for the engine used.
If the goal is 350HP there may not be a significant need for the Carrera intake. If the goal is "Bruce" power you definitely need all the advantages available.
RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8