A 32GB SSD is pretty much useless, way too small for use as a decent OS drive and caching with IRST is not the way to go; save the money and skip the SSD -- or rather save up until you can buy a 120 or even better a 240/250GB.
If this is for a drive that has an OS or programs I would go with a WD Black, but if just for storage a Blue is fine.