Get the GR. Stick it on your credit card. You won't notice in a year but you'll be happy you did.
To buy today on Amazon with free returns:
Bright and clear - AT VM540ML (stretch to the 740 or 760)
Musical all rounder - Ortofon MC3Turbo
More body, a little warmer and musical - Nagaoka MP300 (stretch to the 500)
Be warned. All of these require 20 hours to even start sounding their best so don't jump to conclusions.
Do I need to get a Schiit Mani Phono Preamp for MC and MM Cartridges?IIRC, you have an old receiver. Yes, you should get the Mani for now. The phono input in the receiver will not do justice to the new table. Speaking of which, at the very start, I recommended you get the Mani before dumping the Pro-Ject.