965 rears can be mounted on NB 911s using a radial to radial adapter.
VCI makes some.
Vehicle Craft Inc."VCI" Hi-Performance Brake Upgrades For Porsche Cars
I don't know if they have an adapter for the 3.5" spacing of the 930, you can ask them. The calipers will have to be machined as well. I like this approach though, as it allows to fine tune the height and center of the caliper.
If you're looking for more rear bias, you can also play with mixed pad compounds and use higher coefficients rear pads in your 930 calipers to achieve a similar ratio.
Pagid's coefficient curves are available on their website.
For example, 0.45 pads in front and 0.50 pads in rear would achieve a similar bias as the 965 calipers.