An electric fan won't cure your problem . . Or at least, they generally don't . . nor will a different water pump.
Low speed heating tells me that you aren't flowing enough air through the radiator, or . . The radiator doesn't have the convection tubes necessary to carry enough coolant through that radiator.
When did this heating problem start? What did you change before it manifested itself?
I'm not being a hardass, but you sound like you're ready to spend a bunch of money to keep the problem you have right now . . .
Another thing. If you're just going to drag race it, start with an adequate radiator, and then put a single electric fan on it that covers the whole radiator back with it's shroud. NEVER put the fan in front of the radiator . . Simply because you put all the motor and shroud supports in front of the fan and cut it's efficiency by about a quarter . .