Ive read in another forum that the 325 Cobra will not fit, something about the tailboom sits about an inch higher than the T-rex.
if you do notice the MT325 Cobra isnt exactly scale.
I run an electric tailmotor in my elevated tail bodies and with this , Im limitless as to where I can place my tailrotor. When going scale, you should expect to do some mods depending on the body style youre seeking. On my elevated tail bodies, I usually remove the stock tailboom, belt and all thats associated with the taildrive and i then install an electric tailmotor to drive the tailrotor.

I do two versions of the cobra, one is the Marines version and the other is the Army version. Personally I like the Army version better (I was in the Army and served as a Helicopter repairer) My Army version is about 20-30% bigger and will accomodate all 450 size helis but for the elevated tail, I do recommend removing the tailboom and go electric tailmotor which I think would be easier than doing a mechanical elevated belt drive tailrotor. There is a mechanical elevated tail drive system available for the T-rex but I have not purchased one and I dont know much about it. I switch scale bodies so often sometimes (depends on what I feel like flying) that each helis elevated tail rotor is in a different location. The mechanical belt drive elevated tail drive unit is not a one size fits all for scale applications.