I had a Summit universal 31x19($180) in my '89 and could never get the temp to go more than 5 degrees over the t-stat rating. It was a real tight fit, though.
I should be getting my direct fit aluminum radiator from summit tommorrow. It cost 279$. I hope it works out ok as I have not had any problems with summit brand prouducts yet.
I just ordered my second fluidyne radiator about five minutes ago. I had my first one for 6 months until one of the welds broke. I have a feeling it happened because I ran a catch can with no return. I was thinking about switching to another radiator company, but have decided to get the same one seeing how I already retro-fitted my ramcharger fans to it. I'm also ordering a 180 t-stat, a coolant temp sensor to boot, and a new cap. All i'll need is one of those dcc units for the fans. I made the mistake of ordering the harness with the ramchargers - I have to turn them on manually (does anyone know how i can set it up for them to turn on automaticlly with the harness I have now?)