The only thing that isn't proven, IMO, is the need for true-duals on a 2.5L - which is not to say that there are no gains over a single setup, just that they have yet to be documented.
2003 Mustang GT 5-Speed, FMS 4.10 gears, Dr. Gas O/R X-pipe, Flowmaster cat-back, BBK CAI, C&L intake plenum, Accufab 75mm TB, Steeda Timing Adjuster -
13.70@102.23
(SOLD) 2000 Cougar V6 ATX with many mods -
15.93@86.97
