Toyota Repair: Celica 01 GT, celica gt, manual transmission

Question
I am getting ready to take over the payments on my friends Celica GT '01 model. Well, me not knowing what has been done to the VEH on it's 106k mile life history, what should be done to ensure my Toyota will last 250+ miles?

Also, I HATE AUTOMATIC! Not only will I decrease the weight of the car taking the automatic transmission out, Is it possible to convert it to manual? -- Money is not a factor, but if I can save some let me know.

Appreciate the time and concern with replying to this matter.  

Answer
Even if you can find someone that is willing to change from auto to manual transmission the cost would be astronomical, not only the transmission would be changed but also the wiring harness, the computer, the pedal assembly, the shifter and consoles. These model celicas used two types of engines, the 1ZZ-FE and the 2ZZ-FE, as far as I know only the 2ZZ-FE used the manual transmission so this could present another problem because if the engines are not the same the transmissions will not bolt up.