Well they turned up quick,nice surprise to get home from work to!
I first grabbed a magnet and it didn't stick to the pipes which means quality is not as cheap as i thought they would be,as to the many sheets of 1.2mm 304 no.4 s/s that i have used from china and a fridge magnet would stick to them without hesitation!
Will have to give them time to see if they crack or not.
To my surprise they do fit a GX twin weber manifold,where i thought it might touch on number 4 primary it has a good 3-5mm clearance but number 1 only has 2-3mm clearance between them which is cutting it a bit fine for heat transfer to inlet manifold.
I measured tube thickness on primary,36mm/1.5mm wall so they are 33mm id and outlet is 50.8mm/1.5mm wall so 47.8mm id!
All bends are machine mandrel not press bent.
Overall they look pretty good for the money so time will be the test to see how they last!