Originally Posted by jackei
Just want to see how does it impact the performance and MPG. 
I'm driving a 04' automatic crossfire, travel about 50 miles daily, 20% local, up and down the hill, and 80% freeway, around 70 mph.
I have been getting about 23.3 MPG, using Premium 91 octane Top tier gas (FYI, I always use Shell, occasionally 76 and Chevron). I just switched to regular 87 octane gas, probably for the next two months for a more accurate result. I expect a less MPG, but I want to see the actual "mile/$". 
Holy Pistons Batman! What an idea... Jackei.
The key word here is "holes in your pistons".