Windows 10. Where we're going we don't need legacy software, but if you do, then download PowerShell 5.0 instead.

SQL Server Management Studio 2016 and SQL Sentry Plan Explorer (Free). Don't forget that you should use Import-Module SqlServer instead of SQLPS for new work.

Did you know SSMS now has a built-in plan comparison tool? But SSMS also has query plan display bugs so for the time being you'll still need both

DBA Tools for PowerShell. If you're not coasting to retirement then start scripting now before it's too late, PowerShell automation is a disruptive technology. Oh, and come join the SQLCommunity (#DBATools, #General and #SQLHelp) on Slack.