96 to 98 4.6L GT's are notoriuosly underpowered compared to the 99+, due to introduction of the Power Improved (PI) heads in 99. The advantage would be a head swap on the 96-98, because you could pick up some compression. By all means not a bad car, but you would need to throw some money at it to get some decent HP out of it, especially if you are looking at some form of power adder. Search stangnet and corral for more info.