CapeX5, I would NOT do that. On top of what others said, you will be sacrificing a lot of handling/stability. There is a reason why tires are staggered on the X in the first place. When I acquired my 4.4 it came with 255/50R19 all around. When I upgraded to staggered it was day and night. I could not believe someone drove it without.

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"better the devil you know than the devil you don't"
2003-03-04 E53 X5 4.4i M62 [SOLD]
2006-03-16 E53 X5 4.8iS N62s
2006-03-28 E90 325i N52 [TOTALED]
2012-09-06 F30 328i N20 (CEO's)