Apple Logic Pro /LogicExpress Discussion

I currently have 7.1.1 on my G4 PB and 7.2 on my new iMac Core Duo.  
Having just learned that 7.2 is not only for intel machines, I just 
have 2 questions to restore clarity:

1.  Is there any reason not to install 7.2 on my PB?
2. Are non-UB plugs useable in 7.2 on a G4?

Thanks,

Gregory