the only difference i see is the tour's better keyboard
im pretty sure the curve2 has 3g and wifi as well
It does have 3g but it is the slower EVDO rev 0. Tour is on EVDO rev A which is definitely faster. It does have wifi, will also have gps(the 8520 does not have gps). Only other difference is world phone, 3.2mp camera with flash(curve2=2.0mp camera without flash), and higher resolution screen.