My understanding is that the main problem with in hub motors is unsprung weight which plays havoc with ride and handling so much tweeking needs to be done with suspension to make it work. Protean Electric and China/VW were partnering to develop a VW Passat with in hub motors. I don't know the status of that project.
Yes, it's all about how much. And it's a matter of choices. So speaking of street sports level power....
The typical large hub motor now is 5hp up to 10hp. IMHO, the 10hp is way too heavy for the needs of unsprung weight. Improving that with gearing, liquid cooling and high voltage/high RPM out there in the wheel is not a good idea.
If your car can live with 5hp continuous in each hub, then you can just make it with some handling and ride left. In a 2F1R trike, that gives 15hp continuous can do as much as 75hp peak if you get some extra cool air in there. That's categorically equivelent to the Elio power band. Truely not a sports car, but very liveable.
So for the super sports version, minitureization is not possible in a hub motor unless you can discover warm-superconduction with super-super-magnets, and cooling would still need to be solved. For now, you'll need something like the inboard solution I recommended previously, or just a huge motor drive if your vehicle design can stand the extra weight and volume involved. That's how the EV-dragsters do it, a huge-huge heavy motor, and the right battery pack/controller.
The e-dragster guy told me the only limitation to his speed was getting a battery pack that fit the truck and dump enough current for 7 seconds. His motor and controller could take it. (he could always double those up too) He could get maybe 2000amps (at 200v?400v?), but would like as much as 4000amps or more (wholey sparks Batman!). His motor shaft was directly bolted to the drive-line, no tranny at all.