soft brushless setup

[gusti]

Guys my son has a supermaxx with a plettenberg maxximum and a schulze controller.
He has also a stockmaxx with some modification. So the stockmaxx has modified Diffs with Integy cases. MIP CVD's and Center.
Now, when the stock motors are over, I think to replace this with a brushless set. Now I think for the modified stockmaxx it would be not possible to handle a similar power like the plettenberg maxximum. For this reason I am seeking something with less power and long runtime. It should work with 12-14 cells.
However, I read about the novak brushless set. Sound interesting, but some people told me, that it is very proprietary. So I had only one choice of motor and controller.
For the same price, I can get a 9920 and a 8l Feigao. But some people told me, this Feigao has similar power like the maxximum has.
So I am really confused. Is there nothing between?
What would you recommend, if you want to do a "light" brushless setup? It should be durable, because I don't want to repair this truck every weekend.

Thanks for your help.