Fully Modded Origin Live OL1 or Stock Rega RB-600?

Wondering if the OL1 with structural mod, full external and internal re-wire and upgraded RCA's would be better than a stock RB-600. This is not the Origin Live Silver; it's basically a heavily modded RB-250. Will have a Dynavector 20xL mounted on either arm on a P-25.

It's counterintuitive to me to go backwards in the Rega line and gain an improvement, especially going from a $700msrp arm to a $575msrp arm, but who knows. OL says the OL1 will outperform a RB900 but, of course, they're trying to sell tonearms!

I can get a great deal on the OL1 ($375 - normally $575) but I don't want to waste the money if it's not going to be a significant improvement over the stock RB-600.