Hi JV,
You can install Reporting Services without SSL. I'm not sure if your second question is regarding whether RS or SSL can be harmful, but I'll assume that you mean SSL.
SSL is a Certificate Based encryption technology. In general, for Internet facing applications, you'd need to get a Certificate from a Trusted Certificate Authority such as Verisign or GTE CyberTrust. For Intranet applications, you could use an internal Certificate if you have a Certificate Server installed on your network. Public certificates are fairly expensive, I beleive in the neighborhood of $500.
SSL is a stable technology and shouldn't be considered harmful. However, there are some considerations to be aware of when using SSL on SQL Servers. For example, if you set your SQL Server to require SSL, which isn't required for Reporting Services, and the certificate expires, you won't be able to connect to SQL until the certificate is renewed or you remove the requirement.
Regards,
Steve
Meddle not in the affairs of dragons, for you are crunchy and taste good with ketchup.