Are you hell bent on buying a PWR one?
I just installed my racepace triple core in my 32 today, went in sweet and it retaines the factory shroud.
From what I've been told by people in the know I don't see a reason to have a radiator so big that it can't retain the factory shroud and fan. Getting a thermo is just going backwards in any case.
If the vehicle is in motion there would be plenty of air passing through the radiator
If you are not in motion or at low speeds, then yes you defiantly need a fan going to draw air through the radiator. A mechanical fan does a better job at this then a thermo. Also having the shroud will be advantageouse in directing air where u want it..
At the end of the day the mechanical fan and shroud will kick a thermos ass if your barely or not moving.. And if you are moving it doesn't matter so much