I grew quite fond of perfect space over the years and I like it better than the currently shipping alternative, ReMatrix. 
Is there any chance that perfect space could be spun off and made downloadable without installing all of Sonar 2 or 3 just to get it?
 

As far as I know, your only option is to do a minimum install of a previous version of SONAR and just install PS.
You don't even need the core program.
 
But I will say, I've had better results with Rematrix than I ever did with PS.

If you are running 64 bit Sonar I would look for a 64 bit alternative.

PerfectSpace had a few tricks that REMatrix doesn't have, such as triggered pan automation. If I still had any of my old projects, I'd definitely go to the trouble of digging PS out of my 8.5 disks. But as I'm starting from scratch, going forward I don't see any reason why Rematrix won't fill the bill just fine.
 
PerfectSpace was a "lite" version of Voxengo's Pristine Space product, which Aleksey has end-of-lifed due to weak sales and as such was never compiled to 64 bits, VST3 or AAX. However, it is still available as a download.

I'm pretty sure you can use the impulses from Perfect Space in ReMatrix Solo, not at my music computer to test at the moment.

I was a big fan of Perfect Space....until I tried ReMatrix.
seriously, just give it a try.

I do not recall if SONAR 2 or 3 have the advanced install option. I know more recent versions of SONAR do. The basic/advanced option is one of the first screens in the install process. An advanced option provides a checklist of the components to install. This would allow installation of PerfectSpace only. That said, I stopped using PerfectSpace some time ago because it was not getting updates and was stuck at 32bit. I like the full REmatrix but prefer MMultiBandConvolution when working with my own IR files mostly because the plug-in does not rely on a database instead using the OS file system for IR organization. In this respect, MMultiBandConvolution is like PerfectSpace. The plug-in often goes on sale for 50% off.

scook
I like the full REmatrix but prefer MMultiBandConvolution when working with my own IR files mostly because the plug-in does not rely on a database instead using the OS file system for IR organization.

 
The way ReMatrix Solo handles IRs is indeed pretty clumsy. I was hoping the full version did it better, but it sounds like it works the same way.
 

The full version of REmatrix still relies on importing IRs into SQLite. AFAIK, all Overloud products which include a convolver import user IRs into the plug-in's storage space instead of reading them directly from the user folder.

I should look into these Impulse reverb's,, I sort of understand what they are but have never tried them. I'm in an experimental mode right now and I'm for once in a few years am trying all those "other" options in my effects list. 
Last night I tried both Breverb and the Blueverb, I found them edgy with very digital tails. Sound fine on a fast songs but suck on ballads.  
So I returned to my trusty Lexicon which for some reason is on the "uncategorised" list?? 
I see "Perfect Space 32"  but I'm not about to go backwards to 32 bit effects. But that said what is the Lexicon? 64 bit? 
I don't see a REmatrix on my list I guess you folks are talking about a none included plugin.