X3 (F25 and G01)
The F25 buying guide covers the N20 xDrive28i and the 35i, and the G01 cars include B46 and B48 engines. Repairs include the G01 rear axle seals (G01 X3 Rear Differential Axle Seals), the hood struts (Hood Lift Struts (G01 X3)) and the B46 and B48 turbo coolant line (B46/B48 Turbo Coolant Return Line). See BMW F25 repair costs, BMW G01 repair costs and the BMW X3 F25 Buying Guide: What It Costs to Fix and BMW X3 G01 Buying Guide: What It Costs to Fix.
X5 air suspension
The E70 and F15 use rear air bags (X5 Rear Air Suspension Bags), and the G05 uses air struts (G05 X5 Air Strut Replacement). See BMW E70 repair costs and BMW G05 repair costs and the BMW X5 Air Suspension Sag.
X5 engines
The xDrive50i uses the N63 (N63 Valve Stem Seals) and the xDrive35d is on the diesel guide (BMW X5 35d Diesel Problems and Repair Costs). The older V8 X5s are on the BMW N62 V8 Problems and Repair Costs.
Shared items
Both use tie rods (Tie Rods (Inner / Outer)) and xDrive fluids (Transfer Case Fluid (xDrive)).