That brake looks interesting. If it really does work at reducing redirected noise, it shoulde be a good buy. With a light-kicking rifle like the SU, a brake is more for appearance than actual function. I'd be interested in hearing about how well the Levang actually reduces perceived noise. By all means, buy one and let us know!
I'm considering an early M16 flash suppressor for my SU16C, mainly to have something to protect the muzzle (plus the kewl factor). BUT, if the Levang lives up to the claim, I will look into it.