As far as I know, you don't need to do a fresh install; Haiku (and BeOS) detect the hardware you have when they boot up. The installer is quite simple, just copying files. Nothing is customized during installation.
Windows has different kernel builds for single vs multiple CPUs and other things (like BIOS SATA AHCI mode which gets baked into the registry or not installed if not detected). On the flip side, Haiku has all drivers installed, even if you don't need them. But then hard drive prices are cheap enough that the extra space used doesn't matter.