I have only used the Scorpions on my RC51, and I've heard of problems with quality, although mine are fine. They sound very nice, not too loud. To be honest though, I would put an Akrapovic on a ZX-9R. Nothing else.
Have a Scorpion on my TT. I've had mine for about 2.5 years and no problems with fit/finish. Looks and sounds great. Deeper exhaust note than stock and a touch louder, although not obnoxiously so. Sounds a helluva lot better than the D&D's I've heard.