If it gets wet, it could definitely be an issue. It’s actually an easy fix if you google how to crimp coax cables and buy the tools to do it. I mention this because that cable may be a long run and difficult to replace. If you’re going to do it yourself, it’s a 5 minute job to cut that end off and recrimp and new coax end on it, with maybe $20 in cost to buy the tools needed and connectors.

I would look for things on ebay. Google the model and find the type of RAM it needs. Same with disks. Disk drives are pretty universal, as long as you have the trays needed for that server. You either need 2.5 or 3.5 inch SAS drives. I can’t tell from the photo. If you don’t have the drive trays, make sure you get trays for your drives from ebay too. SATA drives will also work, but you’ll have better luck with SAS drives since they’re enterprise spec and tend to be more reliable and last longer. With RAM, the only thing that’s really different from desktop RAM is that you want to make sure you get ECC(error checking) for a server.

If there’s a clear path to higher ground, then definitely, yes. Your car is fine right now, but if the water level goes any higher and gets into the electronics, you’re screwed. If you can easily drive it out of the water and get it parked in a non-flooded area, without having to drive through deeper water, do it.