Only my own experience with a 2000 156 1.8 SW (140.000km) and my present GT
2005 (65.000km now)
Reliability 100%
Besides the regular services no need to top up the engine oil, only 1 or 2
bulbs blew and 1 flat tire.

ALFISTAGJ

2002 156 2.0 JTS Turismo. Mileage 55k miles. This is the first variant of
the JTS engine that Alfa developed and now use across the board (I think?).

Reliability good.Currently experiencing a splutter, but service next month
should sort it. 'Teething' problem with Knock sensor when new. Suspension
has required work at every single service so far. Mainly bushes.

Performance good. Fuel consumption also good - generally gives 37/gallon,
but can manage 49.5 on a 60mpg run (once in 4 years!) and down to low 30s
when driving fast.

Insurance - group 16 !

Paintwork all perfect, except the black triangles which the wing mirrors
attach to. The black paint over the aluminium is starting to bubble and will
soon all flake off (just as my 1997 fiat Marea did).

Cloth on seats is starting to show a little wear, but not very noticable
except on the drivers seat arm rest.

2000 2.0 twinspark 83000 miles

Black box swap at 4000 miles
Starter Motor failure at 35000
RPM sensor failure at 66000
Temperature gauge faulty at 47000
Radiator corroded through at 81000
Wishbone/suspension work needed at 36,000 and 60,000

Lots of preventive maintenance of course - third cambelt, replacement
water pump, 6k oil changes, or the above list might be disastrously
greater. But providing you do the tlc, 156 twinsparks can achieve
tremendous mileages.

It seems to be the case with 156s that the bits you expect to pack up go
on and on (tyres, brakes, and above all, exhaust - this is still 100%
original and got through it's seventh birthday MOT earlier this year),
while what should go on and on (cambelt, suspension components, cooling
system) doesn't!