As mentioned above you can remove the pins to alter the stock pose. I didn't make any other modifications besides adding a round base instead of the stock oval base. A while back I bought several of the 120mm bases from the Privateer Press website, Proxie Models also makes round 120mm base.
Adjusting the tilt of the torso make a big difference in how dynamic the model looks and you can try different poses if you get some sticky-tac or poster tac/putty to test fit parts before you do the final gluing. When the Riptide first released I really didn't care for it due to the goofy crouched pose, I decided to repose it and it was like finding a whole new model and it's since become one of my favorite Tau models.
Here's a shot of the resin casts. Magents added so they can be switched out with other weapons.