More power: Euro SS Headers?

I was researching this for a bit, and came to the conclusion that they are every similar to US spec headers in shape, but the collector and downpipe are actually larger. Supposedly, they were providing a substantial boost in power under the curve.

Here the thing though, these are for E36 cars, so they would not have a 02 sensor bung for the post cat 02 sensors, and I'm not 100% sure if they E36 Single vanos Exhaust ports are like the E46 Double Vanos cars.

Anyone?

A number of people have used these on M54B30s in race cars to good effect. Port shape if anything will benefit from the step to the larger primary tube.

The O2 bungs shouldn't be an issue, as you will need to add them behind aftermarket cats installed downstream of the headers anyway.

I'm in the process of fitting euro M3 headers to my M54. Beautiful pieces, they are.

One issue is that the M54 block is physically slightly larger than a steel block due to reinforcing ribs. Slight pipe clearancing may be required.

Pictures and dimensions vs stock (or ebay style) if you could. The Superprint (and replica) pieces have an even bigger collectors than the stock S50B32 versions.

Here's what I'm talking about. (I lifted the picture from somewhere else).

Last time I tried to fit these the #1 or #2 runner, I forget which one, was impinging on the horizontal rib of the aluminum block. I then test-fit them onto an M50 someone had on an engine stand and they cleared by 1/4".

My conclusion is that slight external difference between M54 and M50 blocks effect the way some headers will fit.

Full disclosure: I also pushed my #1-3 collector up an inch to clear my subframe, so they are no longer identical to stock.