i agree with whitecrystal. mine's been on for 2 years and not a prob, although no real gains IMO. i want to get it dyno'ed this summer to see. i do sometimes get a belt chirping sound if i get it revved out in 2nd. it seems that the rev limiter has been reached and accelleration stops, until it shifts to 3rd. but i have f*cked with the rev limiter and shift points.
08 f150 xlt with xtr package, white supercrew, 4x4, 5.4 with 3.73 LSD, 6.5' box, Sct and..SSI 87 Gen6..87 Perf MPT. Gott's mod