I believe that the Cox Tee Dee 049 (ebay), Fora (Global Hobby in San Diego) or Picco 050 from Doug Galbreath are 1/2 legal. Fora also makes a 060 which is F1J legal (??).
There is a motor called a cyclon that is supposed to be the top dog. A second mortgage is probably in order for the cyclon.
You can also pick up accessories like bladders, timers and TD needle valves from Texas Timers.
Sorry I can’t be much help. I just started my TD for the first time last week.
The “hot” engines available new for F1J are the CS/GZ, Profi and Cyclon with a tip of the hat to the Cyclon. Several other makers made engines for F1J but they have fallen by the wayside. These are avaialble used but keep in mind, thye are just as expensive as the Cyclon and not parts available. The current price direct from the maker is USD 288.83
For a full breakdown of all the F1J and 1/2A engines – see http://www.gregorie.org/freeflight/f1j/index.html
The TeeDee is not competitive in anyway. Modern 1/2A-0.061 engines turn up in the in the mid-30,000 range and a tricked out TeeDee might make 19,000 RPM. I do know one hot flier than got his TeeDees to hit 21,000, but he is a master machinist and engine builder.