Re: 2003 Navigator/ Supercharger
I'd go with a ProCharger system. They can be custom tailed to your Exp. The 5.4L is a good, solid platform for a s'charger and ProCharger systems cost a bit more, but they also give the most gains per pound of boost; they also include a proper intercooler to protect engine components!
'11 Ram Quad Cab 4x4 SXT 5.7L HEMI (stock); 48,500m
'06 Pontiac G6 GT 3.5L 220hp; 64,000m
'12 Chrysler 200 Limited 3.6L 283hp; 28,000m
'99 Taurus 3.0L 2V Vulcan 145hp; 154,300m - Traded
Amsoil in all vehicles!