2009 5.7 to 6.4 Conversion?

[Spartan040]

I might possibly have a line on a low mileage 2009 Challenger R/T with the 5.7 Hemi, and while I want to go after it, I've always wanted a 392 Hemi. How difficult would it be to stroke the 5.7 to 6.4? I've found some different kits to do it.
http://www.ebay.com/itm/Chrysler-Modern-392-HEMI-Main-Balanced-Scat-Stroker-Kit-1-48508BI/331749080936?_trksid=p2141725.c100338.m3726&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20150313114020%26meid%3D702005804db9426fb2d73440b912ddcb%26pid%3D100338%26rk%3D2%26rkt%3D7%26sd%3D360936326382

http://3rdstrikeperformance.com/index.php?main_page=product_info&cPath=35_3209_829_8527&products_id=15204&zenid=f1add555273a2d6115407fc0330c34b7

Which of these looks to be the better kit?
How much horsepower could I expect to gain from stroking it alone?
What cam should I select to provide good power without hurting MPG too much?
If I decided to stroke the motor, could I still eventually go FI with a turbo or supercharger provided I do something to lower the compression? What would I have to do in order to do that?
What heads should I look at using?

Thanks!