What Novo said, but also I highly doubt that anyone who would baulk at collecting 50 CSDs would bother with a guardian ruins run which is kind of a grind as well, only with a creepy atmosphere.
I didn't go deliberately collecting those, or the Decoded and Aberrant ones for other engineers. Just scan all the ships in range every time you leave a station or enter a res site and you'll eventually have 50 of each from normal gameplay.
The heat sinks... the nice upgrade is "extra ammo" because it gives 4 uses rather than 3 from a heat sink, so you can match heat sinks with SCBs easily.