only really important on N/A cars i think mate, the auto specialists one is just a copy of the standard item, apart from port 2 and 3 where on the original they join together before entering the turbo, also most people with big bhp still swear that the standard item is good enough.

being a tubular copy i would of thought there would be some slight improvement, even just for the looks !!!!.

ive bought from that seller, hes reliable, i cant comment personally on how the autospecialists item performs as the tubular manifold i bought from him was a custom 1 off item made by hayward & scott, it was only about 500 miles old, a work of art, they obviously know what theyre doing at hayward & scott lol.

dave.