your problem sounds more psychological than anything. are you and your friend using different string guages? also, the string spacing may be slightly different on the 2 guitars. i know the spacing on my rgt42dx and my rg7421 are slightly different. it seems that the spacing on the rg7421 is a bit wider... it's more comfy for me than the 6er but i've seen no difference in speed per se. they just feel different.
"... and on either side of the river was the tree of life. The leaves of this tree were for the healing of nations."
"He causeth the grass to grow for the cattle and the herb for the service of man."
"Lifes too short to hate Floyd Roses."