few questions about ZEN cart

Have downloaded Zen cart and have some questions:

Is the ZEN cart suitable for selling digital downloads(ebooks)? I tried some stores, but still no find some good one for my needs. Is there ZEN cart version customized for selling digital downloads?

I need to have few options:

• use Paypal for payment,
• automatically transfer the customer to the eBook download page after they pay via Paypal.
  (currently I have e-store where after the order is complete, buyers have to click to return to the website to get the download link. Then they need click to download an item, and get link.)
• download link protection: links need be dynamically generated and hide the true location of the file on server. Links need be set to expire after fixed time period. There is simple Linklok for Paypal script that do exactly this tasks. Since this script need know what item to deliver, the store need pass through to Paypal the item_number's of the ordered products. Does it possible implement Linklok into Zen cart?

Does Zen cart pass to Paypal the item_number's of the ordered products?
Does Zen cart use Paypal's IPN?

Zen Cart handles digital downloads, if you install the cart with the demo products you will see that there are products to show how this works,

no zen cart does not pass the item number to paypal using IPN,
there is no need since you get an invoice generated by Zen Cart.

Does Zen Cart will automatically transfer the customer to the eBook download page after they pay via Paypal?
What's about download link protection? If it does not have it, does it possible implement Linklok into Zen cart? (but Linklok need know what item to deliver, so store need pass through to Paypal the item_number's of the ordered products).

Once the customer pays through paypal they will be directed back to your site,
there will be a download link on the page,

and yes they are protected, you can even limit the number of times and the number of days a download is available,

you can also choose to keep the downloads storage file above the root,