Has anyone had success with a preamp with a Marantz PM 8006?

I previously had a PM 8006. It is known for having a good built in MM phono stage. I d experienced a nice improvement in vinyl playback by adding a Rothwell MCL step up transformer and using an MC cartridge. 

I currently have a Garrard 301 (Oil bearing) turntable with an SME 3009 non improved arm with a Ortofon 2m Brown Cartridge.

"Garrard 301 (Oil bearing) turntable with an SME 3009 non improved arm with a Ortofon 2m Brown Cartridge."

Spend more money and get a "better" main amp and phonostage.

The table setup warrants a substantial amplification upgrade.

@rpppr Again, I agree with @tablejockey.  Your TT set-up out classes the Marantz 8006. That said, with a vinyl system TT is the most important component. Regarding the purchase of an outboard phonostage, would you consider upgrading the integrated amplifier thereafter?

I agree with both of you.  I just purchased a [aor Klipsch Heresy IVs and need to wait "for the dust to settle" to make another significant  purchase.