Phat Bodies use a wind tunnel to test their bodies for micro buggies like the Losi Mini-8ight. Even in 1/14th scale there is a noticeable difference between bodies. They discovered even with the micro buggies at speed there is a significant amount of aerodynamic lift on the front end, which the cab forwards bodies help to counteract with the tall front windscreen, plus it gives the airflow time to smooth out before hitting the rear wing.
The top drivers notice a difference in handling, and those are the people who have developed and tested these bodies. When you consider they also notice a 5w change in oil if they consider them better then there must be something in it.
If the cab forward bodies really made no difference then the manufacturers would make bodies that make the buggies look a lot prettier than the monstrosities they are now. Unfortunately it means we are stuck with these bodies for the near future.
And on that point, the speeds you reach will dictate whether there is any advantage in using a particular body.
At our local indoor, it's just too darn tight for aerodynamics to factor in (25'x40'). Even my destroyer buggy (3,300KV on 3S, 24/81 gearing 2.25 stealth) can't hit speeds over ~15 MPH and still be able to slow down in time for a turn. At such low speeds, body design really isn't a factor.
On the other hand, you get out on a track where you can hit 30 or 40 MPH, yeah, it makes a difference.
"When you are dead, you do not know you are dead; It is difficult only for others. It is the same when you are stupid."