It should...he'll have to have either the Pacesetter h-pipe adapter kit to bolt the GT catback up or have a shop fab up some piping from his cats/midpipe to the catback. The fitment should be the same though...All the stock piping for 94-04's was 2.25" and the overall vehicle dimensions weren't incredibly different.
I'm surprised you still have that catback lying around
12 Black GT500 SVT PP l 2.6 Pulley/Idler l Airaid l o/r X l 305 NT555R's l Recaros l
04 Azure Blue Mach 1 / 03 Sonic Blue 3.8 / 14 Sterling Grey F150 FX4 402A 5.0 / 11 GT500 R.I.P.