People regard titanium as being some sort of brilliant material. It is not necesarilly that good. Its best properties aren't so much its strength per se, but its corrosion resistance, toughness & high temperature strength. Most of the titanium mined in Australia is turned into white powder, not alloy.
In any case I think you will find that the rims are aluminium and simply coated in Titanium which give them the rainbow effect. There is no reason for them to be any heavier, stronger, weaker or substantially different than any other Volk rim.
From memeory the proper Rays rims are titanium outers with alloy centers, no coating on the rim.
Im not saying its the best meterial out there, i was just correcting miss information.