I've done this in reverse with my G32. I simply bought a .40S&W barrel from Top Gun Supply http://www.topgunsupply.com/ and it drops right in without modification of any sort. You CAN use the same magazines, but there are differences between the .357 and .40 mags and thus you should go ahead and buy extra mags designed specifically for the caliber you're shooting.
PB
P.S. Yes, they are reliable.