MakeNSISW v2.46
After a BIG INSTALLER DATA i've got this result:
Install data: 1498563711 / -1479390358 bytes
so obviously that the number used for the summary of the package are ints. Even if it's a rare case of installation, I think It's better to use unsigned int.
The size is now displayed as a unsigned number, for really large files that compress well the result might still be wrong...