First one of the following articles depending on which version you are using:
Many of the files are optional.
To reduce the size of the SyncBackPro.exe file itself you can use free executable compressors suchs as UPX. To reduce the executables size (by around 75%) use the following command line with UPX:
upx -9 -f SyncBackPro.exe -o SyncBackProUPX.exe
This will produce a file called SyncBackProUPX.exe which is considerably smaller than the original SyncBackPro.exe file but does exactly the same thing.