I would say that it is just as likely to have issues as on the 2.2 and the 1.9 diesel.
The reason you don't hear about afilures on the 1.9 Petrol is that not many of them were sold.
It isn't a torque issue which causes them to fail, it is a lubrication issue due to a design flaw within the box.
We agree it is lubrication problem, likely that's why a lof ot Opel/Alfa M32 gurus say to add 0.5L more of oil than in official spec says. My gut tells me that if there is poorer lubrication, then it is more of the problem for M32 setup with higher torque engines such 1.9JTDM/1.75TBi than for non-turbo charged 1.9/2.2JTS engines. That does not of course exclude cases where JTS will also suffer for the issue, but likely problems happens at later time and/or on fewer percentage of cars.
Reading posts on AO I have impression that there is quite a lot of real complaining on M32 (like I will never ever buy acar with M32 etc)
M32 is weak side of relevant 159s, all right, but my point is that I would no worry for future - if there is no roaring today, I would just change oil + add extras I mentioned, and enjoy driving beautiful car. Good chance all will be fine for years. As I said in earlier post, I did 85kkm with roaring bearings, and that did no cause any harm to gearbox. I suspect that fresh oil and some gearbox oil additive I can't remember name today I put in that time stopped gearbox degradation. Full repair cost was only EUR300 and issue disappeared completely, all good since 10kkm.
I bought another 159, with another M32, and I sleep well, and I recommend that approach to other M32 owners.
To top it all the 1.9JTS is underpowered in a car of the 159's weight.
depends what you expect from the car. For me TBI was underpowered, so I did ECU mod to 240BHP/370Nm, and still I won't say it is a rocket.
But a lot of people are happy - I remember 7 years ago I driven 1.9JTS and my impression was good (though I driven in that time 103BHP hatchback, so JTS seemed like much more powerfull car)
Not sure if on your market it was offered 159 1.8MPI - in Poland it was - it was old type Opel engine with 140BHP, I never driven one, but those who own this, again are rather happy with it. This is only engine 159 which tolerates LPG modification well, and where mod is chip, so you can drive the car cheap (half price of petrol in Poland), so for those who just want comfortable car, drive carefully, that is still fine. Depends on needs.