I have tried the bear and the lime and phex is the best.

But I have quite a number of files from the other 2 that were not completed. Is it possible to transfer those files over? Will doing a partial download in phex (there by creating a *.dl file) and then replacing the file with the larger file from the other client work? I dont want to try it if it ruins my downloads.

Yes, this should work. But to be sure you should test it a keep a copy of the original file. But as long as the filename is the same a resume download from should work even if the download was started from a different client. Just make sure it's the same file with the same size.

Gregor