Does Wurtz-Fittig-reaction involves Sn1 or Sn2? Following mechanism is commonly proposed for the Wurtz-Fittig-Reaction: 



Picture from Wikipedia

The red marked reaction steps is a nucleophilic substitution (SN). I suppose that this is a SN1 reaction, with an intermediate carbocation, rather than a SN2 reaction. In my opinion the resulting carbocation is good enough stabilized throughout the aromatic ring and therefore SN1 should be preferred, moreover because of the steric hindrance of the aromatic ring.

Is this assumption right? Thanks a lot for your help.
Aryl carbons cannot go through SN1 nor SN2 substitution reactions. SNAr involves the creation of benzyne intermediate. The mechanism is this:



The benzyne has sp hybridized carbons, which should be linear, but forced to be bent. Therefore it can be attacked by a nucleophile, and become sp2 which isn't linear.

Notice that the carbanion can also attack the adjacent carbon. It's a special phenomena for this type of reaction. The mechanism was confirmed by carbon-14 labeling (Organic Chemistry/Paula Bruice, sixth edition, page 692).