I've got the SC Project low can, the carbon one. Very light, looks good, sounds good, I've never taken the baffle out but it's plenty loud enough with it in - if anything, slightly too loud for me. Has a bit of a rasp rather than a deep woof, if you know what I mean. Around town it's loud enough that drivers can hear you, but at higher speeds you can't hear it over the wind noise.
It's passed two MOTs with it installed, the first time the guy commented that he had to be a bit generous to let it pass; the following year it was the same tester, but he didn't make any comment at all. For reference, there's no definitive noise limit for motorcycles at MOT time, it just the tester's opinion as to whether it's too loud. Since MOT testers are regularly checked by 'mystery shopper' types taking vehicles with known faults that really shouldn't pass, they can sometimes be quite strict about it.
Definitely no stop on it for the centre-stand though. If you need one, look elsewhere or be prepared to get someone to weld something on it.