Help me fix my Rx-8

So first off, any idea how long my engine will last me if its running around 6.5 compression??

And to pass my emissions i need to fix codes P0661, which is Intake Manifold Tuning Valve Control and P2259, which says Secondary Air Injection System Control "B" Circuit low.

I've read that the valve just needs to be cleaned but what is the best way to go about this?

Thanks!