Im just about to do mine, an been told you can do the swop an will be fine to drive until properly mapped.
Im sure someone ran there ko3s on revo stage 1 for some time and said that there wasn't much difference when they went to revo stage 2, think they said it actually ran abit better on stage 1!.
I might even try running mine with a MBC an see how i go as loads of guys on Vortex forum are running them an stay there fine if u up them abit, but it you up the MBC to much it will cause stutter on half throttle, which i dont want.
Then i'll get mine properly mapped when money allows.