If its hp you want, just buy a Saleen SMS 5.7 supercharged Challenger for around $58K. It has 500+ hp- same as the 6.4.

If Dodge produces a Challenger with a 6.4 in 2010, it will probably be a limited production model and cost almost as much as a Saleen. Look what they just did with the 2009 SRT by bumping the MSRP up $2K.