|It's your money.|
"the first thing is the airflow"
The cases are laid out the same. All you need is a single 120mm exhaust fan in the rear of the case plus the power supply's cooling fan. No other case cooling fans are required.
PC airflow and heat â€“ a cooling guide
"more space upgrades, cable mangement"
Really? I don't see it:
inside XPS 8300 case
inside Sharkoon MS140 case
"less dust inside my computer"
The front intake fan will suck even more dust into the case.
As to whether the connectors will fit, I have no idea. The case wiring/connectors aren't shown at the Sharkoon website or in the manual. If they don't match up, you'll have to carefully remove each metal pin/wire from the plastic connector(s), then plug them individually to the corresponding pins on the motherboard.