Vacuum Pump Questions?

I lost a ring on my engine so when it is at the machinist getting freshened up I am thinking about going with rings for a vacuum pump setup.
I need advice....brand...type..pitfalls...ect. I know the basics but want to know if the $ vs. reward is there. my current combo is maxed out parts wise so this maybe the last area for gains.
Going on my 500 wedge run of the mill 9 sec backet motor.
will send specs if needed...