Is that an ebay style manifold?  Most people say these crack, but I have not had any personal experience myself.  I would brace the manifold/dump pipe to the block so it doesnt take all the weight.
 
With the dump pipe, is it an ebay one (no cat)?  I bought one (eastern states seller - cant recall his name) and the bolt holes in the turbo flange were incorrect (you can see it if you put the gasket on the dump flange, one hole in particular was out by ~5mm) and it would not fit on the turbo studs.  The guy sent me a replacement which was identical. and also did not fit.  I ended up getting one of the SARD copy dump pipes with built in cat as part of the group buy that COGS organised.
 
Cheers

Did you buy the dump pipe from ebay?  I did, when it didnt fit, he sent me another, which was identical.  He tried to tell me its my car but I took a picture of the gasket over the flange and you can clearly see the holes are incorrect.  In the end he refunded my money including return postage of both dump pipes.  Its not fit for purpose and can not be used, you should ask for your money back, which will mostly pay for he cat dump pipe.
 
I would brace the manifold so its not stressed.  Not sure of which manifolds are good, havent really looked into it although others will no doubt be able to help with their experiences.
 
Cheers

Cant make this one, but I hope to come to at least the start of one soon.  Not in the MR2, that is still not functioning :(
 
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