I'm pretty sure that the engines you have in your part of the world are the same as what we have here in NZ. In that case, if you can get hold of a 4D56T, it is a way better option than the 4D55. Apart from the engine size (2300 vs 2500cc) the 4D56 has a number of better/improved features over the 55. The 56 has a better tubro/wastegate assembly than the 55, as well as a better designed head (although they are interchangeable). If you can get a Post-91 4D56 (Gen II), then it's even better, as they have roller rockers as well as an increase in HP over the earlier 56. The 56 will bolt up to the 55 trans as well, and the mounts are the same.

Hope that helps!