I'm starting to compile info & specs on the radiator options now. If it's anything like my previous compilations, I probably won't touch this for another 5 years... Anyway, keep in mind there's more to a radiator than just its core size (or worse, its end-tank size). The Mishimoto, for example, seems like a fantastic deal until you realize it only has 7.25 fins per inch. It's big core size means it can probably get away with it, but its definitely not ideal. I'm going to guess that the Megan is probably in the same ballpark.
Stock: $425, 2-row?, 1.15" core, ?? fpi
CSF OEM: $185, 2-row, 1.3" core, ?? fpi *AT
CSF Race: $340 (discontinued), 2-row, 2" core, ?? fpi
Koyo OEM: $130, 2-row, 1.25" core, 20 fpi *AT
Koyo R: $360, 2-row, 2.1" core, 20 fpi (requires modification to fit factory fan shroud)
Mishimoto: $240, 2-row, 2.2" core size, 7.25 fpi (requires modification to fit factory fan shroud)
Megan Racing: $245, 3-row, ?? core size, ?? fpi
PWR: $500, 2-row, 2.2" core, 18 fpi
Fluidyne: $475, 2-row, 1.5" core, 17 fpi