Electrically, there is no real performance advantage in taking it all the way to the pump. The wiring upgrade is mainly supposed to remedy the voltage drop problem, where any up-size reduces voltage drop.
The only issue though is that the Aeromotive fuel pump also requires that the wire handle higher current than factory. I'm not putting my neck out there, but my opinion is that since the remainder of the wiring is in the tank, ambient temperatures will be lower and therefore the smaller wiring is okay.
DO make sure that there is plenty of dielectric grease on the sending unit connector though!!!!
I suspect that the old grease oftentimes dries out and allows a little corrosion and arcing to occur, which generates heat and can lead to fires. Any existing problems will be aggravated with the higher output pump.
I also think that it is overall safer to not try to add any new connections through the sending unit, since a little time and moisture could create a major safety hazard.