i think i do !! i installed cold air intake , then a couple o days later i got them to do my eng and tranny software !! very noticable diff imho !! well worth the money !! my 03 4.6 was 1 car lenth faster than my neighbors 05 4.8 from 0-120 !!
i cant wait till i do it to my new 4.8 !!
