no particular reason actually. i had a whipple on order because there weren't any fast whipples out there at the time, i think they look better too but i got tired of waiting on it. weeks had gone by and i was at a stand still with the car, i picked up the phone and called kenne bell, had the new piece 5 days later! im not up to speed with the larger compressors and if 1 is more efficient than the other. either way they both make a nice piece but both company's are difficult to deal with