EFILIVE is the best way to do it, but the cheapest way is to take a 18MM spark plug anti-fouler and drill the center out big enough for an O2 sensor to pass through it. The install the anti fouler with O2 sensor into the downstream O2 bung. The O2 fouler will slow down the downstream O2 sensors reading enough to make teh ECM think the cat is still there and prevents the light in most situations. Otherwise download teh tune and turn the codes off for the downstream and defeat the cat safety portions and flash it back in.
