1) As it says, "(a move takes precedence over Class B)." So it's automatically Class C.
Also, if you decide to rip something out (Class A), it specifies that you can't do anything else (that's what makes it Class A). If you later want to take that thing you ripped out and add it somewhere else, then you've started a new refit, and you're adding something to where nothing was removed in the same refit (Class C again), except that now you've taken two separate refits, and so risk taking the Quality Rating hit twice.
2) Yes it does (Class C). If you add heat sinks to areas where you've ripped something out, that would be Class B instead, per the rules.