Just my opinion. (disclaimer) The TC33d not only has a more powerful engine, it is a larger displacement engine as well. The TC29 engine is a tuned-up version of the TC25 engine. I recently bought a TC30 with the same engine as the TC33 just has less fuel delivery. In my limited experience if you are getting hydro, get all the hp you can get, especially if you plan to do heavy pulling chores like disking or boxblading.
Jerry