Buying from Trusted Forum Sellers

[Glacier]

I've been lurking around TRF and WUS for quite a while now, currently pondering on purchasing my first sub. I know that it is significantly cheaper to buy from a trusted seller here on the forums, but I have several questions I hope the more experienced members can help clarify for me:

1. Some sellers advertise the warranty card is named and stamped by an AD, does this actually matter given the name on it will not be my own?

2. I see a lot of FS posts selling BNIB for over 10% off retail, sourced from AD. How are they able to obtain these at such low prices when ADs aren't giving much of a discount to the popular SS models? Do they buy them in bulk?

3. Are the listed prices generally negotiable?

4. Has anyone ever had any negative experience with the trusted sellers on this forum? My biggest concern is getting a piece shipped to me that isn't in good condition (esp. in terms of accuracy), given that these types of sales are often final and difficult to refund.

Thanks in advance for any insight you can provide!