Being the ZomB creator, I may be a bit biased, but please try ZomB (0.7 is amazing compared to 0.6)
Legality: DBPacket is 100% legal, TCP (the default) is pending a decision from the GDC, but should be legal, considering what they have said in the past. Both are always available at home, and the TCP sending TO the robot is really nice for lots of variables needing tuning.
As for corrupting the ni-rt.ini, I've tested it, and it has not corrupted mine, but I would back it up (
ftp://10.xx.yy.2/ xxyy is your team number), run the installer, and compare the new ni-rt.ini (it also saves a backup), and make sure it only added ZomB.out to the StartupDLls list. If not, either manually edit it, or replace it with the backup it automatically creates (ni-rt.ini.backupTIMESTAMP). you can also manually install it
If you have any questions, please ask!