Ready to change a bunch of parts.
 

Questions:

1. Ready to change radiator, radiator cap, expansion tank, drain plugs and all hoses as part of preventive maintenance. Question: what other parts do I need (i.e. clamps?). Water pump and thermostat are only 1.5yrs old so no plans to change.
2. Where is a good place to buy spark plugs and oxygen sensors other than the dealer?

Thanks.

Shouldn't need any clamps as they are built onto the hoses. (if it is a 3.0i you may need 1 small one for the vent hose to the top of the radiator to the expansion tank)

And I think ECS tuning should have the plugs and sensors you want/need.

Thank you. I'll check out ECS tuning.

Question: how many oxygen sensors are there? I checked ECS Tuning and the site mentions 4 (2 each front and rear). I thought there are only 2 sensor, 1 front and 1 rear. Prices are $100 front each and $110 rear each for Bosch. BMW parts are twice as much...

Thanks. Let me know please if I need 2 or 4 sensors.

There are 2 before cats and 2 after (bank 1 and bank 2)

Thanks again, Weasel.

With my E38, they told me to only change the front two o2 sensors, the rear ones rarely fail which is why they are higher, a different car...but still family..