Hello Paul and all.
 I complete the my first RX-8 13B p-port engine and I measured power and
trq. This short lenght of intake dont good for me. Engine had cca 210 HP /
9000 rpm. Then I  used intake tubes cca 14.9 inch and engine had 257 HP /
7500 rpm, but at 9000 rpm engine had only 222 HP. We used EFI euro 4
computer. What should I do to that I have 300 hp / 9000 rpm? Because I used
this engine in competition car. Thank ´s.

Respectfully, Michal from Slovakia.

Do you have a wide band mixture monitor on it?
If so what was the mixture?

Looks like you have the stock RX8 exhaust manifold on there.
Try a header 32 inches long. About 1 meter.

If you want to get really trick try something like this.
Make the outer runners 32 inches long and the inner runner
16 inches long. The theory  is the center RX8 exhaust port
pulses twice as often as the outer exhaust ports.

Paul Lamar