How to choose compatible hardware with IBM systemX?

Question

Iron

There is a server platform ibm System x3550 M4 release October 2014.
https://lenovopress.com/lp0038.pdf
According to the spec, certain hard drives and certain memory go to it. Those pieces of iron that I picked up by part numbers stand like a cast-iron bridge.
memory - 49Y1406 - $ 100 but no one has the required quantity in stock, you need 20 pcs. They offer an analogue, 49Y1407.
HDD - 81Y9730 - 300-350$ per piece for 1Tb.
Is it possible to find compatible hard drives or does ibm (lenovo) somehow flash the basket \ controller \ disk so that nothing but the original fits? Who faced with the selection of iron for IBM equipment removed from support. Native sleds are screwed with tricky torx bolts, you can’t unscrew them without a special bit.
Will the memory work?
The dudes from Lenovo's northwest sales department are sent to distributors, and those to partners, and they somehow do not respond very quickly to my requests.

Answer 1

Flash the controller with a similar LSI firmware (google for "lsi firmware controller model") and any disks will work.
Any memory similar in terms of DDR3 IBM/HP/DELL/Samsung/Kingston, etc. will do.
Or order from ebay / aliexpress according to
part numbers Also look at the MyPlayHouse channel on YouTube, there people are fans of IBM / Lenovo and talk a lot about their hardware and compatibility