Buy the Lemforder kit from one of these vendors (FCP EURO or ECSTuning), replace everything at one time front and rear. Easy process, now that your SAV is over the 20 year mark and over 100K is is time for a refresh. One time for the next years of fun driving.
When you buy what was an expensive vehicle at low prices you can be sure that every maintenance item was ignored until you. So plan now for:
Suspension
Axle Boots
Brakes
Cooling Systems (Rad, big hoses, and little hoses)
Window Regulators
Oil leak repairs (Oil Filter housing, valve cover, Oil Separator hoses
Change all the fluids in the transfer case, diff and trans
Save the upgrade stereo until the vehicle starts, drives, and stops every time.

Daily driver? Power wash that suspension and hose down with WD-40 as you are in the rust belt so as you work, the bolts and nuts will come off....

Good luck and welcome to the family!

__________________

2005 X5 4.8IS
The Blue ones are always FASTER....

Current Garage:
2005 X5 4.8is
2002 M5 TiSilver
2003 525iT
1998 528i
Former Garage Stable Highlights
2004 325XiT Sport
1973 De Tomaso Pantera, L Model
1970 Dodge Challenger T/A 4 sp Alpine White
1970 Dodge Challenger T/A 4 sp GoManGo Green
1971 Dart Sport, “Dart Light” package
1969 Road Runner 383
1968 Ply Barracuda 340S FB Sea-foam Green