Best option for headers + cats

[elrichmeister]

On the RE ELS

https://www.rogueengineering.com/Rogue-Engineering-E46-M3-ELS-Equal-Length-Section-RASP-Pipe-Section-1_p_1433.html

it mentions it was designed for the Euro Manifold, However, in specs it mentions:

• This item does NOT eliminate catalytic converters on US vehicles!

So does this mean it will fit, but not really equal length on US Manifolds?
I'm interested in this, mainly to test it. My Section 1 was has a non factory tube welded in that doesn't look factory, it still has the original factory resonator. I'm assuming pervious owner had 2nd resonator, and at some point it was put back to a "stock" configuration.

[dHam_Slow.46M]

dumb question, but are the megan headers NLA? don't see anything on their site besides axle back and all the retailers i've found ahve it either back ordered or "pre-sale"

[theOracle]

dumb question, but are the megan headers NLA? don't see anything on their site besides axle back and all the retailers i've found ahve it either back ordered or "pre-sale"

I’m not sure if they’re NLA.
i looked and the site I purchased them from last spring has them as “Pre Order”

[theOracle]

I’m curious about this RE ELS section 1

Can someone explain how this will not rob power?
With such aggressive bends how will it allow exhaust gas to flow? I’m not an engineer, so this is a real question?
To an amateur like myself it looks like it would create an obstacle for the exhaust to get through