I ran a universal Griffin radiator in my last Malibu. It was the 31x19. No major modifications to make it work. No quality issues at all. Cost me 179. Only reason I don't have it is because of a short departure in to V8 S10's instead of G-Body's.
Now I have a triple pass Summit Racing radiator. Same size 31x19, although this one was a tad tall. It still fit though. Think I paid the same 179 on sale. Again no quality issues. Happy with either one especially given the cost.