So i bought a 2001 Lexus automatic and put a 2003 Lexus engine and manual transmission. The mechanic said I had to go to a dealer to get the manual EC you and cluster changed is the true?

 

I can't help you with answering that, but I think he means ECU as in Engine Control Unit.

 

I did the swap before to manual conversion in my old 2005. Yes you need to get an ecu and also cluster as well as the steering wheel along with dash harness and manual engine bay harness to make it a true manual conversion. The 2001 has different wiring connectors compared to the 2002-2005 which are plug and play. It can be done but repinning and such will be involved which can be a PITA.