I see your point on the lightweight.
Still it's a pity that link does not allow a 550-600 motor to go in. I love 600's
I'm pretty sure that after the very first go-fast bashing period, my goal would be to make it more of a scale-crawler and for sure it will have weight in the (beadlock)wheels.
A 550 will probably fit with a little modification. Overall though I just don't see a need for any more than I can get with a 540 and a 3 or 4 cell LiPo.