Get yourself a T45 instead. They come in 96 and up GT's and Cobras, not hard to find. Those 4.6DOHC's ('specially the 99's) make more power than most Mopar small blocks and do NOT live easy lives, and most hold up pretty well.

Keisler supposedly make s a kit for the T45 in a Mopar now, its cheaper than the TKO kit, but still a bit o money. Maybe you can buy everything but the tranny? I've been thinking about this swap for my Challenger, and i asked them about it but they said they make the kit to mate the engine, but not the kit to install it in the car. Shifter location is off or something like that.