i just came across the X1 prototype created by adrian and its almost 20 seconds faster than these f1 cars so as a single seater that would be the pinnacle, it included a fan like the one used by brabham bt46b, and a gas turbine engine. heres a brief overview
"designed with pure speed in mind, rather than to regulations. It is therefore far superior to a Formula One car in terms of speed and handling. Its extreme specifications are hypothetically capable of taking 20 seconds from the current F1 lap record at Suzuka[1]. It was said to have a top speed of 249mph and weigh 545kg with around 1509bhp. After much tuning the X2010 was capable of achieving a top speed of 307 miles per hour. The downforce must be turned down to achieve the max speed."
and heres a link to see the beast:
http://www.youtube.com/watch?v=dmtehAZV ... ature=fvwp
Now thats a diffuser
