dannyzabolotny.

Been there, done that. I've removed door panels a few times, to replace different things INCLUDING window regulators. I used to be in the trade, ran my own shop and have seen the differences in finish and quality of various part alternatives.

For the E53 - a genuine one is THE way to go. They are not cheap but you'll only do this one time and be fine for 10+ years - so what is your time work vs. lower quality alternatives make in Turkey or China?

An acceptable alternative is a used genuine one. I did this for a rear door (which isn't used as frequently), cost for the regulator was the equivalent of $35 US - so the time to replace with cost of a new genuine one came into my decision. Similarly I have a good (inspected and properly lubed) left front in reserve for the day when my left front regulator fails (or to help any local friend with an E53). Why used for THIS one? It came from a UK car, so the left front isn't used as much and the equivalent of $35 US was part of the decision for a reserve part. This option naturally wouldn't help anyone in North America.

If you go new, a number of US BMW dealers will give approx 25% discount for mail order (you'll find them as advertisers in the BMW CCA Roundel magazine).

Regardless of your choice, you will want a heat gun or hair dryer to soften up the black sticky stuff to gently peel back the vapor barrier. You will DEFINITELY want to replace the window to regulator plastic clips, which become brittle over time. You will need two of BMW part number 51 33 8 254 781 (about $1-2 each, buy the genuine part at your local dealer) for each front door (if you decide to go proactive) and one for each rear door.

You don't need to disconnect the battery to avoid air bag error codes or related. Leave the car off until it goes into sleep mode (approx 15 minutes after shutting the car off), without the key in the ignition when you do the work.

If you want to lube the window slider felt parts - 3M silicone lube (you can buy in a bottle/brush setup) is a good product.

As you are opening up the door, consider adding Dynamat or similar inside the door shell, it makes a notable difference.

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2002 Euro X5 (E53) 3.0 diesel (M57)
5 speed manual with UUC short shifter.
Pre-xDrive NV125 transfer case (chain & gears).
Factory Xenon headlights, Spyder LED tail lights
Updated vortex crankcase breather.
Motorsport dead pedal, factory fire extinguisher, factory first aid kit, factory F&R mud flaps, factory PDC

Bilstein B6 shocks F&R
Redline oil has replaced "lifetime" fluids (F&R diff, manual transmission, transfer case and P/S).
Dimple magnetic drain plugs in all compartments.