todays motor trend has Steeda's $19K makeover of a x-cab f-150. says they can do the same to a navigator or expy. highlights of what you get are:
vortech s-trim @9psi
mass flow upgrade
bassani headers to tips
3.73's w/shift kit
lightning suspension & wheels/tires
custom seats/dash
355hp/387ft
60in6.0
14.6@94.8

 

This only confirms how good of a value the Lightning really is. Tack on 19K to an XLT and you are well over the L's price.