Hey chap,
I don't know about the 156 but I have the maera weekend 2.4jtd, 10v
It is torquey but could do with a re-map for a bit more 'poke' due to the weight of the car (only has 130bhp standard on the marea)
Never had a problem with the engine, it has never not started.
I've had the cambelt changed a clutch replaced at a good price of £450 for the lot.
glow plugs were about £70 to do at a garage but these only need to be done once every 5-10 years I believe.
All in all a good engine and if you are looking for a cheaper alternative to the 156, then a marea would be quite a good choice.
Darren