Recommended setup and addons for my business: used audio equipment?

I just installed Zen Cart on my unix machine and i wanted to know what would be the best way to set up the software to best suit my needs.

• My business revolves around selling used audio equipment

• Each item available for sale is unique.. but sometimes i would receive multiple quantities of identical items, but since the items are used each would be in different condition.

When i acquire new items, normally each item would be created as a new item in the catalogue. Is it the best practice? Or should I set up an item once, and when i receive an identical item i would just update the photos of the initially configured item? The way i have things set up in quickbooks now is that each new item is unique and i keep creating new items when i acquire new things.. even though the same items have been entered into the item list before in quickbooks.

If i was selling new products, this wouldn't be a problem... but since i deal in used products, i would like to know what the best practice is when it comes to adding products.

• Which plug in would allow me to integrate ZEN CART with QUICKBOOKS 2006 PRO CANADIAN VERSION? I don't know if there's any plug in that supports canadian quickbooks versions.

• I'd like to have good sales /marketing reports and be able to drill down by custom fields. I'd like to see inventory on hand, best selling items, time that it takes to sell a certain itm, etc... Is there any good add-on that does it?

• What's the best administration add-on?

• What's the best paypal integration add-on?

Your valuable advice would be greatly appreciated! thank you in advance!