If you do go with the 94-98 and do a v6 engine swap, you're much better off swapping in a split port 3.8 rather than the 4.0. The 3.8 will bolt right in and require minimal modification, whereas the 4.0 would be more difficult.
In stock form, the split port 3.8 provides pleasant daily driver power. You can also already get them dirt cheap in junkyards
2002 Mineral grey GT 5 speed. Flowmaster 40's catback, Mach 1 grille delete, timing advance, push button starter, Bullitt pedals, FR500 steering wheel, K&N FIPK, Self ported upper intake w/ spacer, Pioneer Avic D3, MGW shifter, MM FL subframe connectors, Mach 1 springs, Bilstein HD struts/springs