To reinforce Sylvan's post..

I ran into the exact same issue this last weekend. I too was tired of stepping over the aluminum running boards... and wanted the aero body kit anyway.

Upon removal of the running boards... the body kit side sills will not fit over the supports. Lucky for me... the dealership is only too happy to sell the side sill supports (Part Numbers 51777207195 and 51777207196) With CCA membership $88.00 X 2.

I "think" these are the same parts that they probably toss every time they jab someone to install the running boards.

In the end... it was all worth it... I love the aero kit.

I hope this helps.