You might take a look at Midway Mustang

https://midwaymustang.com/

A friend pointed me towards them for a pullout IRS for my Mk5 after he dealt with them for the IRS and Coyote for his Coupe build. Looks like a lot of their drivetrain packages are automatics (not a bad thing; automatic cars are probably treated more kindly than manual cars) but I imagine that you could have them break the engine and trans apart for the right price.

Jeff