Originally Posted by FDAUTO

For a compromise in any of the sealing surfaces not large enough to be obvious, it won't smoke itself out with the exhaust pressure behind it. It will simply continue on and go out the the rest of the exhaust. Any trace amount that finds its way out will be inconclusive. For single turbo cars you only have 3 places: manifold to block, manifold to turbo, downpipe.

Unless the chra is not fully seated or the exhaust housing has a crack or something in it, finding the leak will be fairly straightforward. Flanges do warp and cracks do change in size with heat. Whether it be to get louder or quieter, the phenomenon is real. It makes for finding them a little more difficult as you've explained. Scenarios like this are exactly what smoke tests are for.

Checking your flanges for flatness is easy. At a minimum you would be able to rule out the manifold. Then you would check the exhaust housing flange for straightness. Depending on your v band connection type, you can do the same there as well. Wouldn't hurt to replace the clamp too. Don't rule out the wastegate as being a possibility either.

if you can take the manifold and turbo into a very dark space and use a very bright light, pin holes, cracks or otherwise will show themselves. You may be over thinking this. In a single turbo set up, exhaust leaks are very easy to find using the proper methods.