[c-nsp] RSP16 drop-in for RSP4?

[Pete Templin]

We're looking at deploying some RSP16s to replace RSP4s that are running 
low on RAM (obviously).  We're running 12.0(27)S5 on all of our RSP4s. 
Is the RSP16 a drop-in replacement for the RSP4s, or are there any 
feature, IOS, or other limitations we should plan for?

Thanks,

Pete Templin