Zen Cart website updates and optimizations

Hello, we need a skilled Zen Cart professional to help us update, optimize and - in general - make our live website improved. In particular: - we need to adopt a new clean and simple template, or adjust the actual one - of course it must be full responsive; - we need to update, if upgrades are available, the core software and any other plugin/extra application eventually installed; - we need to delete from the server any unused file and folder, including old templates, images, and anything else is not used. We expect you are a Zen Cart expert and so you are able to give us any good advice in order to get the best from the platform, we mean you can suggest us what it worth to be changed or modified in order to have a more secure, stable and good looking store. Information about the live website and any other information about the project will be given only to those who can demostrate they are Zen Cart expert.