Fuji:..,It's the same RB300 arm as REGA just only made for Basis with Basis armboard and VTA. It's kind of cartridge-independed combo. I've listened to it with Benz Glider 2 and I can bet that cheaper cartridge(Dynavector 10 series) will also sound nice in there.
I'm not sure if you can switch to the Graham 2.0 arm but Graham 2.0 itself used is arround $1400?. In that case I think I would change table too to go for real upgrade.