XmlReader in PowerShell

I have an XML of couple of gigabytes. There are no spaces in the XML.

So I wrote a little C# code to split in single files (which has some additional code to perform some stuff e.g. randomizing while testing)

using (XmlReader MyReader = XmlReader.Create(@"d:\xml\test.xml"))
            {
                while (MyReader.Read())
                {
                    switch (MyReader.NodeType)
                    {
                        case XmlNodeType.Element:
                            if (MyReader.Name == "Customer")
                            {
                                XElement el = XElement.ReadFrom(MyReader) as XElement;
                                if (el != null)
                                {
                                    custNumber = (string)el.Element("CustNumber");
                                    output = @"d:\xml\output\" + custNumber;

                                    File.WriteAllText(output, el.ToString());
                                }                                    
                            }
                            break;
                    }
                }
            }

I then parse the resulting files with PowerShell, basically because I find it easier to work with on the server while specs can change and I can on the fly change the script.

So... what is the easiest way to convert the above to PowerShell also, putting [.Net here] before everything ? would I have to read byte for byte just in the case it has "" on the next?