I've been running 8.5 psi all this time and tonight I decided to turn down the boost to 7 and when I did, the car felt like it pulled the same or even a lil bit faster? Is it because my a/f ratio is more optimal at lower psi?

 

sounds as if you fuel maps were a bit off at higher boosts...maybe running a bit rich or lean at 8.5

 

could also be the fact that youre gettin more traction at 7psi.