Hi there,
Marketing Manager Pro for x-cart, and Sales N Stats are two very different programs.
If it's just traffic monitoring you are after you can also buy the Marketing manager Traffic Montior Add on module which will give you good lightweight stats on yours site and will even let you "follow" a customer by seeing thier browser screen as they go through your site page by page.
http://www.firetanksoftware.com/fts/customer/Traffic-Visitor-and-referer-Monitor-for-X-cart-pid-25.html
It of course also comes as part of the marketing manager Pro Bundle too, thought I'd mention since you also have that option too.