Re: How can I have a Xcart dev environmet?
Best is to use your local machine and develop there. Best is if you can replicate or get pretty close to the live environment.
There is nothing special to it you just download the whole site including database and modify config.php to match your dev values.
You can also replicate the site in a subdirectory of the live one or if you have VPS / dedicated server create new site in there