[jbahrami]

I have heard that the PSM light may come on when you convert the RWD on Tiptronic transmissions. You did not mention your PSM light coming on so I'll assume you have a manual transmission.

On my 996tt I converted to RWD by removing the front-drive shafts, front differential, and Cardan shaft. I have no lights and PSM seems to work fine.

I believe PSM would only come on when wheel slippage is detected under power. Since you are no longer powering the front wheels, they would never slip like they would if they were being powered and lost traction.