Because you can practically double the power of a modern diesel engine (at least the 6.4L Powerstroke) for less than $2000 in parts. Check out the article we just released about adding an intake, exhaust, and tune to the SVTP F-350:
http://www.svtperformance.com/forum...uble-power-svtp-f-350-because-race-truck.html
http://www.svtperformance.com/forum...uble-power-svtp-f-350-because-race-truck.html