My thoughts.

4150 CMV barrel vs 4140 barrel on the sport
yawn

1:8 twist vs 1:9 twist
yawn

Mid length gas system vs. carbine gas
*Worthy of consideration*

BCM grip vs A2 grip
yawn

BCM stock vs standard M4 stock
yawn

BCM keymod hand guard with heat shields vs standard guards without heat shields
Worthy of consideration for a plastic handguard... not a big deal.

M16 BCG vs AR BCG
yawn

Upgraded trigger vs standard trigger
A smoother lousy GI trigger... yawn.

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Apples to Apples... given the choice for the same dollar I'd rather have a Sport with a $200 trigger.