Automatic to manual transmission
 

Ok I know I have to replace the engine and transmission to change it over... I'm a tech at Subaru so I know what's going on for the most part.. but other then that what else might I have to change or swap over to go from auto to manual. I know The computer must b changed as well... any advice at all from someone who knows these cars would be most helpful... thank you in advance

The cheapest option for converting a 2004-2005 would be to sell it and get an '8 that came with a manual from the factory.
Find one with a good body and a blown motor for $500 - $1500 and then put a $3000 Mazda reman in.

If your starting point is a 2006+ AT, then it's already got a 6-port motor so the costs aren't quite as high but it would probably still be cheaper/faster/easier.

https://www.rx8club.com/series-i-spe...t-swap-151684/