Yes! That's why it is called IB5+.

MTX fits to the engine, but only the ones that were used for Duratec-HE engines in Focus, Mondeo, C-Max... And you'll need new driveshafts and probably many other things!

Don't mix it up with other engines Ford nowadays calls Duratec! Only the chain driven Duratec-HE (I4, 16V, front inlet, 1.8, 2.0 and 2.3) are the same engines like your ST has.

But yes, it is possible to put the internals of another IB5 into your ST box. And I believe just swapping the engine part of the bellhousing from IB5+ to IB5 might work. But you'll also have to take both boxes apart for this.