Seems you would be better to find an auto 164
however if you insist:
This site might help you
There are only so many auto boxes out there.
I wouldnt guarantee a 164 box would fit, bulkhead closer to engine on a 155 but its about the best bet. You wont need to find only a 164 for this box. I mean if you did just drive the 164.
It seems the Alfa 164 auto used a ZF box.
A ZF 4HP18 too be exact. Same or similar box may have been used on some other cars. Scan through and find any car that had this ZF box and hopefully you will have a better idea which cars
might have sitable donor Auto box. When you have 4 or 5 diferent models you know have the 4HP18 box you have a better chance of finding a second hand one.
I believe the engine block on a TS is a derivative of the Fiat FIRE range. There are a hell of a lot of cars with Fiat FIRE engines in them some of these may also have suitable auto boxes.
Oh if you find a donar from an old fiat you may end up with a car that accelerates like a ******* but is all spent under a 100. Still if you live in Malaysia. The roads may not lent them selves to 3 figure speeds , you may prefer the low ratios.
Some BMW ZF boxes have very similar ZF code however these may be internally and mechanically similar to ZF in the 164 but are completely diferent in that they are aligned for rear wheel drive.
Wiring the "dont start engine in gear" should not be to dificult. "This is important to do!" The gearbox switch only needs to be an inline with the ignition switch circuit for the starter solenoid. Ie Starter motor should not engage with car in gear. "Dont start on ECU sense fault in gearbox". well this is just a new feature that your ECU cant cope with and which you dont need. Auto boxes are pretty reliable things.
Your car, you want to do it why not!
Just dont let some half wits (incompetents) do the job for you.