But you already got a Bren tune which is a warranty issue and yes they can know if you flash back to stock.A bike doesn't spew that much HC, but the trucks with cats deleted are really bad - one of those probably spews out as much as 100 "normal" cars, if not more
10 lbs on the street isn't going to mean much of anything, and it's carried low on the bike. Aftermarket exhaust is also warranty issue
Getting rid of the cat lowers the heat. You are still using all the sensors with the Akra header, you are just dropping weight, lowering heat and gaining another 10 hp of midrange power.
It also somewhat depends on the dealer about the exhaust warranty garbage.