As long as you keep your dosages within reasonable limits, which would be no more than 600 mgs per week, there should be no problems with deca dick if you will use all the proper ancillaries. These would include aromasin for estrogen control, cabergoline for prolactin, and proviron for increased DHT and better sex drive.
Personally, I have never needed any more than 400 mgs of deca per week - I am pretty sure that this amount is plenty for anyone who wants to get prominent results.