Trinity Duo Brushless.
 

Anyone tried one of these? fancy getting a 5.5 for the bj4 and these are a good price, but are they any good?

These motors are the same as the ones that Peak and Orion rebadge. Their are others that are selling the same motor. I use one Orion 5.5 in my 4wd and a Peak 6.5 in my 2wd and I find them very good as they have an internal fan they run nice and cool. And as they have sintered rotors the brakes are good as well.