Mini Tubbed Demon
Yes, you'll need to mini tub, moving the springs inboard won't gain you any tire room without widening the wheel wells inward.
Buy your kit from Reilly Motorsports, I think it's both cheaper and better, the boxes are a heavier gauge, and they are pre drilled in four locations for the leaf springs.
http://www.reillymotorsports.com/store/home.php?cat=276
Regards,
Joe Dokes