According to Microsoft, you need not uninstall Office 2003 or 2007 or 2010 to install this office. You can use both Office Suites.
One thing surprised us that this version does not support Windows XP and Windows Vista. You can use it only when you have Windows 7 or Windows 8 installed!
Computer and processor: 1 GHz or greater x86/x64 Processor with SSE2 instruction set
Memory: 1 GB RAM (32-bit) / 2 GB RAM (64-bit)
Hard disk: 3.5 GB free disk space
Operating System: Windows 7, Windows 8, Windows Server 2008 R2 or newer
Graphics: Graphics hardware acceleration requires DirectX10 graphics card.