After the release of Delphi XE2 and the included 64-bit compiler, we have upgraded RW Net 4 where needed and have had great success doing so: We are now able to create 64-bit applications and the route results are the same as before.
Main advantage of 64-bit are the possibility to work with larger street networks, while speed of calculations are not affected so much. It may even be slower for some operations. We shall get back to testing that detail at a later point.
Expect support for 64-bit in next release.