I think i burnt out my stock motor today. So i was looking at a few after market Brushed motors.

I was on the toyz.com and the Losi insane 370 motors were under the RC18 section, But id like to know for a fact that it fits before i order it. Or if there's any other brushed motors that would work besides stock

They'll bolt right up without any mods.
You might also look into the Trinity cobalt motors or the Reedy Stump Puller.