So I'm not entirely sure where the cat is. Is it this thing? Or inside the muffler?
It's illegal to have any vehicle made after something like 1985 in Australia that doesn't have a Cat. They don't check the roadworthyness of our vehicles unless they're being sold in my state however(They really should, some disgraceful cars out there), so who knows.and you will fail your emissions test (if they do that where you are!).
In the UK we have to do an MOT every year (after a vehicle is 3 yrs or older) which incorporates an emissions test. If it fails, the bike in effect does not become road legal..
Is there a dyno that proves this? There wouldn't be as much backpressure into the engine so I would think that there would be less torque. I am installing my two bros today, I think it'll be plenty loud even with the cat.You gain 2 horsepower. ( But don't tell anyone! It'll be our little secret. )