A 4.6 swap is gonna need a lot of things, I've never done one nor have I really looked into one, but some of the major bits would be: engine, transmission cross member, driveshaft, front k memeber, wire harness, ECU, 8.8 if you want a decent differential, and probably more than that. Usually it's recommended to just sell the sixxer and buy a GT instead due to the amount of money and labor involved in performing a swap like that.
Sold - Black 2000 Mustang GT, gone but definitely not forgotten
- Silver 2007 Corvette
Current - DHG 2001 Bullitt