Ok I'm soon going to put my lift on. Josh's Spacer lift minus the strut plates. RRO 2 inch body lift and OME front struts. 15x8 black steel rims with 1.5" spacers. I need to know what backspacing I should get for the wheels. I'm planning on getting 31x10.50x15 BFG mud terrains.
p.s What backspacing are you running Josh?

If I remember correctly he's got 15x7's or x8's with 3.5" of backspacing and 1" wheel spacers to clear the front calipers.  That'd make an effective backspacing of 2.5".