SLD on SAP PI

I have a PI 7.11 ABAP + JAVA system. I have an SLD in my Solman 7.01.. I seek advise on two things:

1. Is it advisable to use SLD with Solman or should we create a new SLD.

2. How do we transport changes across the landscape. Do we need to use CTS+ ? I have a separate NWDI system for my portal.

Thanks,