This one may be of interest to quite a few people.
This photo shows a Z20LET Coupe engine bay with a standard full rubber boost pipe from the IC to the Plenum. This pipe is knows to expand under pressure and collapse under vacuum.
This photo shows the solid plastic pipe used in the same position on the Astra H fitted with a Z20 series engines. It comes with the rubber pipes at either end and includes the jubilee clips.
This photo shows the Astra H pipe fitted to my Astra Coupe. This was a direct replacement and took a mere 5 mins to fit.
This upgrade serves the same purpose as a "power pipe" does, but at a much cheaper price of £40. The pipe should give better throttle response and should also be stronger and more reliable.
For some reason this new pipe takes a higher route than the standard one. This possibly keeps it away from other items in the engine bay, or maybe reduces heat soak. Could just be a random thing though,
For those interested, the part number of this is 55354106.