Almost all cars today have this huge heavy part for engine mounting:
Im trying do my best to reduse my cars weight. The main point of carbon sub-frame is not beauty, but lightness.
As example, see article about Porchse Carrera GT building.
Only thing I do worry about is that my construction could be not strong enough…
Built properly it will definitely be strong enough, my concern though would be that it would be TOO strong.
Especially being around the engine part, it might be too torsionally rigid causing it to crack easily
if built right.
Which includes at least 10 prototypes of different designs, and destructive testing for each, to show what is good, and what is bad.
Prepare for some work!!!
Anything is possible, they use CF in Porsche Carrera GT, F1 cars, F-35 fighter jets, Space Shuttle.
You would need to get a composites engineer so that you can have it built properly so that it wont be too strong or too rigid like Sifu said cause that can and is engineered into the part. (the size, shape, direction of the Uni-directional CF/woven cloth, # of layers, inserts for threaded parts, etc…
Your talking about a very expansive mold (mold around $25K-100K) and process (prepreg - autoclave) to make suck a thing. Plus post process stress and durability testing would be a lot of $$$
You cant just built something and use it, even if its for a car, you need to deal with DOT and other automotive standards.
Your construction would not come close to the quality strength you would need to make something like that unless you have $250K+ to get it made the right way.
Get it made in tube steel.
possibly SolidWorks software can analize the design before it’s made? Does SolidWorks offer carbon fiber as one of the material choices in it’s design testing?
TET…chromoly tube steel 
Correct me if I’m wrong, but are there not rubbber/polyurethane bushing/mounts connecting an engine to it’s cradle? Wouldn’t they soak up the majority of the torque movement produced by the engine?
I think it would be a great project. Would it be a race car piece or for the street? Dzembak, would you be doing the work, or would you be having another company make it?
Still need to prototype and test them before using it in the real world (except if that IS a test)
Solidworks I don’t know, but CATIA has draping and Abaqus, possibly structural analysis. Check out Dassault Systems for their programs.
Thats a very do-able project.
My only concern would be the skill level of the people laying it up.
I do not want to spend lot of $$$ for it - for composites engineer, etc. It`s just a hobby for me.
Engine is not fixed to subframe directly, it`s fixed to subframe with rubber engine pads. They reduce engine vibration.
Original subframe is two welded parts of moulded iron. Each part of iron is 5 mm thick.