Even though your chassis is cut from 1/4" aluminum plate (!), the rack mount might be subject to cracking unless it (the piece that your new bracket is bolted to) is triangulated more fully. Forces on a steering rack can be surprisingly high and subject to vibration. You do not want a fatigue failure.
Thanks for the suggestion. As you'll see in upcoming posts, more triangulation gets added as a side effect of extending the chassis forward. The pictures don't show it all that well but there is already a lot of support for the rack & pinion mount pads in the chassis prior to adding this extra support.