I have done this the other way around on different cars several times. The automatic to manual would possibly be more difficult and probably is. I know that trans fluid needs to go to radiator. So a new radiator would be a neccesity. Also the linkage to the throttle setup. You are gonna need a throttle setup from a manual to install. So that your transmission and gas pedal can communicate. Also the input shaft will be different. The input shaft from the trans sits inside a bearing in the crankshaft. You will need a different driveshaft, crossmemeber, and thats without even tearing into it. Thus, you will need much more. I would only do this if somebody bet me $2000.00 that I couldn't, seriously. When I did this for the first time, I had one of each car side by side. Same model car and everything except one man. and one auto. So I took out the dash of the manual and extracted the pedals and linkage. This made things so much easier. I had all of it there. If I were you I would buy a scrap car with the essential parts to alter the other with. Leave the automatic the way it is. You will spend as much money chasing parts as you would if you just bought a donor car and left the one car alone. Because if you do both you will be searching for parts for both. GUARANTEED!