How do I revive a tired engine
 

I just did a compression test last night to see were I might stand with my current engine. The needle dissapointed me, only bouncing 3 times max of 70psi with gas pedal to the floor. My only concern is if I have to buy all new housings and rotors. I will be buying the rebuild kit just wondered if it is best just to get new everything or can I use some old parts.

Oh, I did notice a vibration in the motor around 2500rpm and at cold start I heard a slight knock until the oil pressure rose.

It's always great to buy everything new. However, for an engine rebuild, that could make things very expensive. Mazdatrix does an engine build with all new parts and it costs around $8000. If you have enough money to throw around for all new parts, do it. If not, use the FSM to determine what can be reused and what cannot. It has all the measurements you need to do on all the engine parts.