Think it cost me £90 delivered. Essentially any will work better than a cast manifold for N/A, as long as its not terrible quality.

This was just a simple 4-2-1, I bought it cause the standard front pipe kept cracking from engine movement, replaced with the copy and made a flexi pipe for it and away I went. Probably the biggest improvement overall. It just seemed to open it up nicely. The piper cam kit made less of a difference and gave more trouble.