R250 upgradability

Hi,

Just got my hands on a new, unused entry level R250 for 270$

Since the price was good, I did not have time to check the upgradability of the system and I can't find much online about the things I wish to upgrade

So here is my questions:

1:

Can a 2 bay cabled system be upgraded to a hot plug backplane?

2:

If hot plug backplane upgrade is not supported, is there a partnumber for non hot plug drive trays and 4x SAS/SATA cables?

3:

I see in the technical guide that the PCIe slots only support maximum 25w PCIe cards. Can the system support more than 25w cards with the 700W PSU, or is this a limitation of the motherboard?

Thanks in advance :)

Best regards

Glenn