Im just getting some parts together for when I get a hybrid turbo put on and Ive come to high flow exhaust manifolds. Been looking at the Ths and Atp ones for just over 200 pound when I read somewhere that the original one on my agu can just be ported, polished and it will flow just as well. Is this true and is it cheaper? Does anyone know anywhere around bedfordshire that I could get it done? Any help please would be much appreciated.