On the CRJ 200 any time extra fuel or alt gas is added (depends on how much) and the flight is full the the max takeoff weight can be exceeded because ballast is always needed with a jump seater and a fullboat, about an incease of 500lbs(jumpseat+ballast). If you add anti ice and bad wx on takeoff that makes the situation even worse generally bumping pax.(depends on runway length and wx conditions). With all that said if the wx at your departure and destination airport are good you should have no problem. I sometimes commute on CRJ 200 and it is basically a commuters nightmare. Depending on wx I'll choose to drive to a different airport to get on an airbus. Dont know anything about the erj.