I gotta say, I haven't drifted much in GT3. But compared to GT4, it feels a little muddy, grabby,and not as on-the-edge-of-control-loose as in GT4. It is overall easier in GT3. I can't vouch for realism in either case, however, as I haven't drifted in real life. A better person to talk to would be Delphic Reason.