HonsterI tried nutsnbolts_repair on a local server and saw no visual particles and didnt notice my frames dropping or anything so hopefully it works. Also personally I wouldnt remove sniper's muzzleflashes since his hitscan leaves no tracer.
If this applies to all muzzleflashes (ie not just first person viewmodel flashes), if you are using yttriums competitive viewmodel mod, wouldn't it be a good idea to make muzzleflashes more visible for the weapons you hide (generally shotguns, scatterguns, pistols, revolvers and sniper rifles.)