After almost 9 years of ownership, and 130k miles
Here are some of the things you could run into, the ones in bold have personally affected me
1. Active tank, SCR +
DEF injector
2.
Nox sensors
3.
Thermostat
4.
Glowplugs and module
5.
Throttle valve
6.
EGR cooler
7.
Exhaust temp sensors (pre and post DPF, high and low pressure EGRs)
8.
Differential pressure sensors
9.
Boost sensor
10.
Battery - Now on my 3rd battery
11.
Idler pulley bolt
12. Leaky turbo oil line
13.
Pressure converters
14.
Injector 5 + 6 due to water infiltration (broken bulkhead partition)
15.
Parking Brake actuator (EMF Module)
16. driveshaft (depending on year)
17.
Adaptive drive valve block
18.
Door lock actuator and bowden cable
19.
EMF switch
20.
Peeling door handle trim, steering wheel trim
21.
Stripped plastic gear for seat thigh rest motor on passenger side
22.
oil level sensor (35D still has a dipstick 
)
23
. CIC screen backlight
Scared yet? Those are just the things I can think of that break, not even counting maintenance like
1. Tranny fluid + pan
2. Water pump + belts
3. Differential and transfer case fuild
4. coolant
5. Tie rods, Lower control arm bushings, sway bar endlinks
6. Rear air suspension bags
Coles notes: Still a blast to drive, cannot easily find something to replace it that handles family hauling duties but you can still chuck into a corner and have it handle like a sports sedan.
Keep up on maintenance though.