I did my IR before the CPL and my ME as part of my CPL check ride. As the CPL is a VFR check ride I would not have thought it would make much difference to you , however, having said that I did find that my flying vastly improved post IR as they hammer home holding your altitudes and headings, it is also a good confidence builder.
As regards the IMC, if you are intending to do the IR then I wouldnt bother with it and just go stright for the IR.