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 & 91 SSI2 Gen 2..87 Perf MPT and 87 Perf Leading Edge as well. Gott's mod