The stock contipro were installed for the sole purpose of getting better gas mileage. They are low resistant tires that were popular on Hybrids However, all tire attribute are a compromise, so reducing rolling resistant means you lose handling and stopping. The newer low resistance tires are actually better.
On certain vehicles, the aftermarket parts may be a terrible fit. I used to own an Acura Integra that I essentially had to get OEM parts for. The aftermarket parts tend to not fit properly, particularly the brake pads.