I was talking to Adam today about the change between Marlow's tactics of intimidation as opposed to Avon's. Its hard to tell if there really is a difference. Bodie's comments in season 4 after Marlow kills Little Kevin (or is it Lil Kevin?), that Marlow doesn't even bother to find out whether or not someone has or has not snitched before killing them; he acts simply upon suspicion. We see a similar theme revived when Michael questions Snoop and Chris in the car before killing someone (whose name escapes me) simply because they heard he was "talkin shit 'bout Marlow." The nostalgia for a simpler, more just era is a theme that characters return to in both drug circles and police circles. The Wire tends to present such statements in earnest on the part of the characters--see Bunk lecturing Omar--but in the overall context of the show, these statements tend to suggest not a yearning for the past, but an uneasiness about the hyper-mechanization of modern culture. And this indeed is what separates Marlow from Avon. The impression one gets of Avon's "muscle" in the first season (WeeBay, Stinkum, Bird etc.) is of men who simply have the capacity to kill. Their primary qualification for the job is having the nerve to do it without panicking, being impulsive or any of the other problems that we see with Avon's much reduced muscle in Season 3. But many of the images we see of Avon's muscle involve recreation as much as violence. Marlow, Snoop and Chris, by contrast, are always shown "on the job." Even in the most recent episode when it appears Marlow is going into a hotel for some nookie, it turns out to be a diversion for a meeting of Prop Joe's Cooperative. But more than that, Marlow builds his muscle far more efficiently. One of the recurring images we saw in Seasons 3 and 4 was of young black men being trained as efficient killers. Up close, head shot. Further away, aim for the balls. Don't aim for the chest because he might be wearing a vest. They set up simulations with paint ball guns, plan retreats to gorges for shooting practice. They are less a gang and more a militia. The term "muscle" has outlasted its relevance. It implies the use of physical stregnth, and--if you notice--most of Marlow's crew are not physically intimidating. Chris and Snoop are assassins. They would be ideal recruits for Blackwater Security Force.
The larger commentary here is about the marketplace. The man with the most efficient product gets the most business, but in the modern world efficiency means the most ruthless, most mechanical, least human. And this is the disquieting sense that Marlow gives the viewer: that he is almost inhuman in his stolid silence. That he is emotionless.