Keep and reinforce original K member, or go QA1?

70aarcuda said
i got 3 of the qa1 k members in use. One on a dart...duster and demon....all bolted on with no problems...I love the room in the engine compartment.

Three of them? This is is high praise.
Was the engine bay access the primary reason for using them? How much weight does he QA1 K actually save?