Hi and thank you for your interest.
My name is Jan, I am developing AmiKit since 2003 and it was first time published in 2005.
I am known publisher to Amiga community but unknown to Microsoft
And since my software isn't a mainstream one, I haven't gone through the difficult corporate certification process (which is probably not free either).
Anyway, I can assure you that the .exe file is a regular installer.
If you're still in doubts, feel free to use any antivirus program and/or launch the installer in a sandboxed/virtual environment.
Hope it helps?