I'm not aware of such a modification, but there may be one.
If you are going to do this once, and ambient temperature is not too high, I wouldn't worry too much - just keep an eye on the engine temperature. The turbo will be working pretty hard pulling that weight - as with any turbo car, after it has been working hard, when you stop, you should leave the engine running for a couple of minutes (or more) before switching off.
If you are going to do it repeatedly, it may worth looking into the radiator modification for such a heavy trailer. I also believe towing heavy loads is not going to be good for automatics, but may be wrong here
2.5-16v 1990 90,000m Astral Silver
2.0E 8v 1986 107,000m Black