what super t said. the hemi swap is not cheep. unless you have a doner car, and really good fab skills. headers and motor mounts are expensive. (to buy) and super cheep to make. then you add in the electronics and it can become daunting and expenisve if you need to buy them. now you can look at going with a carb, and it can be done cheeper, the modman intake from indy appears to be the best route to go (cost and versitility) comaired to the others (edelbrock, and XV motorsports to name a few) then you will need to coil pack controller for spark and there is only one company making it that i know of, and it is MSD. they call it the "Hemi6" my guess is its just a 6AL box that is set up to recognize the hemi tone ring pattern. unfortunatly the wireing harness is sold seperatly. and costs more than the "hemi6" box.
i am in the middle of doing this swap as well, and decided to install a cute little pair of turbos into the mix, i figured if i have to fab up a set of headers anyway they might as well mount to a turbo, and then i decided it will be easier to install 2. so now i gotta rethink the induction (carb or efi) im was wanting to to carb, and nitrous but now that i an going w/ the twins i dont rreally want a blow though carb and have been thinking EFI....
sorry back on topic, the wow factor will be worth it in the end, to swap in the hemi. but the expense is there to keep most from attempting it. the cost of the motor is the cheepest part of the swap.