Only way to suppress noise is with a suppressor, for flash I've read good things about the Vortex flash hider. I'm assuming we're talking about 5.56/.223?
The best for lowering noise and flash signature is a suppressor.
The best at lowering flash and also not too hard on the ears is either the AAC Blackout or Smith Vortex. There's been numerous head to head tests with both of these and in every head to head comparison I've found, the AAC Blackout nudges out on top. It's almost amazing just how the AAC pretty much completely removes 99.9% of the flash signature and hard to believe that something can actually improve what the Smith vortex has been able to achieve.
The best at throwing sound away from you, especially in a SBR is probably the Noveske KX3 or Troy Claymore. They're not the best as a compensator or hiding muzzle flash, but they do throw all the sound away from you towards your target. The KX3 adds back pressure for SBR's that have trouble cycling. The Troy Claymore is smaller and lighter if you don't need that added back pressure.
If you want a good all round flash suppressor that is also pretty cheap and relatively easy on the ears, the YHM 5C2 Phantom flash hider is an excellent value. It's basically an advanced A2 type birdcage flash hider and almost as cheap. It does hide the flash a bit better than the A2 and won't break the bank.
I guess it's a good thing you are not too proud to ask, but I find it interesting that you are in the business of selling AR parts and accessories, and you look for this kind of information here.
I would think that someone in the AR business would have the answers to this type of question.