Ax15 Trans

AX-15 is similar to the Aisin Warner R154.
Austrlians run/ran them and the W57/W58 (smaller versions) in Valiants and holdens and fords
all usually equipped with a small block or 6 cylinder engine and in the ranges of power/torque you would imagine..

popularity dictated by ease of purchase. loads of toyota trucks and cars in Oz
and easy(er) access to half cut crashed bodies and salvage from japan.
they imported these transmissions by the container load

AX-15/R154 used in europe and japan in drift cars usually 2 litre turbo efforts with big HP often created by rediculouse RPM capability and a lot of forged expensive parts

gonna depend how you drive and what you use the car for.
some cutting of torsion bar cross member may be necessary unless you have access to full range of shifter set-ups numerouse fore/aft offsets for passenegr car and truck use

the parts potentially in japan/Oz though....

just like tremec t5, for everyone who says never broke one, you will find a handful who turn the things into parts soup time and time again.

late model (99-2003) mustang t5 and a machined none-world-class chevy s10 tail housing probably fits with little or no torsion bar cross member cutting, and potentially easier to achive acceptible driveline angle. need a hole in the middle of the tunnel for shifter and a swan neck stick to put it under your hand

BUT i guess the AX-15 gives you a bellhousing that fits? if it doesn't easier to make an adapter for a box that has a perfectly round input bearing retainer rather than the odd shaped bolt pattern for the Aisin boxes

bellhousings and adaptors to fit most things to most other things
https://dellowconversions.com.au/

Dave