Please do your best to answer each of my three questions in one email. Something, I have found that emails that have more than 1 question won't get answered. Thanks!
 
Question 1
Does Viart have the capability to allow a user into the website via creditials only? In other words is it possible to give access to the website only after username and passwords are given? We have a site that should only be access by our sales reps, not the general public.
 
Question 2
I see that Viart has a customer type selection. Does this feature allow the logged in customer type to see things only related to that customer type? For instance, if we have different price levels for the general public and distributors, when a distributor logs into our site, will the distributor prices show on the site versus the general public prices?
 
Question 3
Concerning the above, if we have 4 different levels of distributors, and each level get's their own pricing scheme, is this possible? In order words, when Dist. 1 logs in she gets dist 1 pricing. When dist. 2 logs in, the site shows dist 2 pricing

1) You can use an .htaccess/.htpassword combination to allow entry to any website as well as set up "Sales Rep" as a ViArt user requiring a log in..
 
2) Yes you can have public/trade pricing.
 
3) Ive been having a look at the new 3.3.15 beta and I think this will do what you want.
Theres now an option to add user types to a product so if you create 4 user types of distributor you can assign products to them each with a different price structure. They have to log in to access these prices. You could do this via csv export/import

..and you can also assign users to categories