btw I also do this same thing in the charade GTti exhaust manifold - but in that case - we have to saw through 2 bolt holes to de stress it - It is due to this very reason that the charade always burns head gaskets from the #2 cylinder.. the manifold gets very very hot when on full boost and tends to expand greatly - but cannot as its bolted solid as one giant piece. so it tends to warp - The heat sink for the exhaust ports is the manifold itself, which is now not in contact because the manifold has warped - which warps the head and overheats this little portion - causing the coolant to work hard and eventually blow the headgasket. When doing a head rebuild - I always measure the exhaust and inlet manifold facings and head to block facings for warping, the manifold facings (usually slightly warped on the exhaust side) then need to be hand smoothed perfectly for a perfect flush fit - and use copper antisieze on the nuts to tighten them - but the nuts should be the lock collar type ones whose lock collars actually grip the thread. If worn out replace with new - they are cheap about Rs 10/nut
This also is the reason why 1JZ GTE also warps - the exhaust ports are stupidly small and the manifold was designed by a chimp. On the other hand look at a Nissan RB26DETT exhaust manifold - every runner is separate with its own 2 nuts to tighten - PERFECT
I have seen mechanics in Pakistan enlarge the coolant holes in the cultus headgasket saying that it needs blah blah or it will blow the gasket. What they were overlooking was a faulty design.
