Exhaust manifold leak

Last summer I bought new exhaust manifold because the old EU4 manifold was warped and had a crack in the collector. The new ones has been leaking as well. I don't know why, if it is a quality issue from the factory or if I have managed to warp them myself.

I've been asking around my local workshops if they could help me, but they all have been shaking their heads saying it would be too troublesome to fix the primaries at their milling machine and that it would be too expensive and not worth it. The last one gave me the suggestion to try to simply use some sand paper on a flat surface and grind them myself.

So I did.

I was sceptical at first but I think this will work!

I also went to a welder - Zanders - and had my silencer mounting brackets reinforced. They used to have a bit of flex and maybe that could be a part of the problem with the warped manifold. I still have a bit of flex. If this doesn't work I'll try to mount the silencer to the forward roll cage mount.

I made the brackets myself last summer. I think it is the third attempt, the others has cracked after track driving.

Read here to get an idea how it looks like on the car.