Sorry to bug those who would know....but l no longer have a lift equipped shop ;( and the x351 is getting a bit clunky over road bumps, etc.
May l ask, which suspension arms are the most likely to need replacement, front and rear? (car has 120k miles, so far)
On many vehicles, the lower aft arm bushings seem to be "first to fail" but not sure, on the x351 range

Any advice would be well appreciated, thanks

 

The rear lower have soft bushing on front and hard "bearing" bush aft. Easyest is to change whole suspension arm for rear if needed. No neef of lift, easy to do by just jackstand.
Most wearable suspension part by far on x351 platform is on front axle.
Lower front arm, so called "banana arm", have fluidchambered inner bushing. Earlier versions of these last as low as ~50t Mil, but latest Lemförder ones seems to double it. (also depends how vehicle is driven.. These arms handle braking forces)
I have +200k miles on clock (+320t km) and i have fourth set of "banana arms". (i do some track days time to time, so sometimes i notice when it let go on under heavy braking. The oilchambers fails inside of bush and bush turns soft causing wheel angle changement under pressure)
If you feel some vibration on steering, spesially when braking these arms may be the reason if brakedisks are straight.
Also very known wearable part are upper suspension arm balljoints or bushing, front and rear. Again most economy are to change whole arm, because Lemförder (OEM) are well available.
(somehow i still have original upper suspension arms)
Parts are relative cheap and quite easy to change.

 

Thanks, l will change those first and see how it goes 🙄

 

Note: It is possible to change the front "banana arms" without lift, but the inner bush bolt is bit tricky to access just with jackstands.
Engine undercover have to remove to get access and you need to crawl quite far under to see the inner bolts. Use good quality stands! 4-wheel aligment is needed afterwards.

 

Keep in mind many of the suspension arm bolts are designed to be tightened and torqued to spec in the "loaded" position when the car is sitting on its wheels, not in the air. If you torque the suspension bolts when the car is in the air the bushings will wear out in short order.