That "ovular grey box" is the Capacitor, it's needed to start the compressor, no it cannot be bypassed (acctually it can but then the unit won't work
That "Tar" is probably cork tape, it's like the "seal string" that come's with the Prometeia phase change unit's.
The Cap tube should not be insulated, rather it should be wrapped round the suction line, this allow's the refrigerant to be subcooled.
When the refrigerant is in it's liquid state inside the cap tube it is not cold, once it enter's the evap. there is a pressure difference, this allow's the liquid refrigerant to change state, while changing state it absorbes alot of energy, hence "Vapor Phase Change Cooling".
When we talk about sub cooling, it just mean's that we are further cooling the liquid, the suction line should be the only line that is insulated.
Ohh.. if the pipe is kinked then you can try to sort it by using a pair of plier's and pinching gently on the opposite side of the pipe, however if you have a flaring tool then just tighten up the clamp and the kind this will sort it