Copacetic

This SSD tier list puts them in a similar rank, while this one puts the A2000 as the slightly higher performing drive. The main difference (other than slightly different read and write speeds) is that the SN550 lacks DRAM. Both have a 5 year warranty so you should probably just go with the cheaper one. If you were splitting hairs, the A2000 will probably give you better performance, but both will be good enough.

It seems like you have a slightly negative pressure. While there are the same number of intake fans as exhaust, the intake on that case is restricted in comparison to the exhaust fans. Perhaps try and increase the intake fan RPM / decrease the exhaust fan RPM?

Well you would expect the next card in the Titan series to be better than the previous one...