The ESC will be a limiting factor.

On the other hand, if 666W per side ain't enough, you're in the wrong weightclass.

But, the Speed 900 setup as you propose runs a tad fast, doesn't it.
42km/h is a tadoverkill.

So, why the persistent use of the 22.2V? It's not if a 2450mAh 3S Lipo is that expensive.