Front strut top mounts and bearings. The bearings seize and spin in the rubber. That wears the rubber bush but I believe it also contributes to the steering pulling and might even cause wide wheels (as on 100HP) to flutter. New top mounts cost about £20 each.
Another issue is the open threads on alloy parts. Rather than drill and tap blind holes, Fiat drilled them right through allowing corrosion into the threads. Broken bolts are not uncommon. The "fix" is to treat all open threads with ACF-50 - use a syringe to quite a dollop into the open end of the holes (alternator, clutch housing, gearbox, brackets, etc). It's a deeply searching water splaying oil that's used on aircraft frames. The places where I used it allowed bolts to come out more easily. Where I did not the aluminium oxide clag at the bottom of the bolts stripped out the threads.
Cam chains on the Multijet diesel. The single row chain is adequate for 100,000 miles but after that you are on borrowed time. Change it along with the oil pump and oil sump pan. Cost is about £200 for parts. Fail to do it and costs will double as you will need a set of valve rockers and you might trash the engine. It's a great shame you can't fit a dual for chain.
Exhaust catalyst outlet pipe bracket. The mild steel P clips are cheap but they "evaporate" very quickly (mild steel against stainless pipe). Leave it flapping and the pipe will fracture at the base of the catalyst.
Clutch master cylinder can mimic a failed clutch. You cannot buy new hydraulic seals and Fiat will try to sell you a pre-filled pipe and cylinder (@£180). A new cylinder is under £60 and one person can easily bleed the fluid. Additionally, the hydraulic pipe QD coupling is often corroded solid forcing you to replace the slave at the same time. Just change the master and then the slave if it needs doing.