[Efthreeoh]

I'd like to chime in. I have a 320,000-mile E90 with an N52 that I've had since new and I have my E86 3.0 with the N52 (that I basically for my second DD when the E90 is on the rack being repaired) . I DIY everything. I did all 9 coolant hoses on the E90 at 236,000 miles when the car was 8 years old. Upon removal and inspection, I found that none of the hoses needed replacing. Modern coolant hoses are pretty much lifetime parts IMO. At 90,000, I doubt any hoses need replacement. Check them of course for cracks and legions just to be sure, but I'd bet they are all in good shape. If your coolant reservoir is toast, I'd get a new cap as well it's only $12 more. BMW coolant hoses are expensive because of all the fancy (stupid) connectors they use...

I checked realOEM.com. I find it unusual that there are no o-rings to replace with the reservoir tank.

Being that your car has M54 in it, it doesn't have the waterpump/T-stat issues the N52 has, so I'd leave them alone. Not sure if dbarton62 was referring to the N52 thinking your car has one. The water pump in your car will start leaking before it fails as all belt driven pumps do. Replace it when it fails.

My 2 cents.