simplemarket use on a network of sites

Hi, I have a number of sites on a multisite installation.

I just wanted to check that where each site on the multisite installation uses the Simplemarket theme, that any customisation to the theme on a site by site basis will be restricted to each site only.

Let me know anything else I need to know about having each site use the simplemarket theme.

I am looking at this one as I suspect it is the only WPMU theme that is responsive for marketpress.