4500 meters is just under 15,000 feet. I haven't driven an X5 there, but I have driven several different naturally aspirated vehicles to that altitude (Ford pickups, Ford Expedition, Bronco, GM pickups, and various Isuzu/Nissan/Toyota jeep-type vehicles. Quick answer: you will go slowly. You spend a lot of time wishing you could pull the next gear.

The rule of thumb is 3% to 3.5% power loss for every 1000 feet of altitude above sea level for a naturally aspirated engine.

In my experience, vehicles didn't mind the altitude, they just lost power.

That was different than turbocharged vehicles. Turbocharged engines automatically compensated for the altitude, until you hit the limits of turbo rotational speed (with catastrophic results)

While 3300 meters is much less dramatic, at 4500 meters make sure you keep a clear head, as the altitude affects people differently. Drive safely.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue