You can't get that from NAR files. You will either have to do it using navicli/naviseccli or collect SP collects. You will have to have access to tools that can parse through the SP Collects. If you have access to USM (Unisphere Storage Manager) and install it that app will actually create a repository directory under C:\EMC. You can use the "ArrayConfigToXLS.js" file to parse through SP collects.
I have all of the performance data, but I need to extract the sizes somehow.  
Anyone know how to extract LUN sizes from a nar file?