I'm not on a Mac, so l can't choose which version (32-bit / 64-bit) of Reason l install on my 64-bit Windows OS.
But yeah l can confirm that Reason 6.5.2 seems to install as 32-bit on a 32-bit Windows XP Professional OS.
I look foward to installing Reason 6.5.3 on my Windows XP Professional OS laptop again, alongside Acid Pro 7, l hope it works - l just need to free up some disk space on that laptop.
So again, were you able to "remix" Reason songs via Rewire, whilst recording them in Acid? I note you mentioned something about doing that with a driver on Reaper.