Thanks I will give the IX a try. Currently have Bosch installed last year by po and even though they looked good (checked them 10k miles later when doing valve stem seals) at this point I will try everything before doing my intermediate levers.

Iridium IX part# is 6441

Laser Iridium is 4294

Corrected the posting
Thanks for catching that. I was using my iPad and could not read the NGK site correctly.old age moment.
The back ground on the two Iridium plugs is the fact that the 4.8is used the first generation Iridium plug as the IX version came after production. The difference is the metal in the center electrode

Ok cool, replacing mine ask we speak

If you want to see how much plugs make a difference in idle and tip in acceleration, install the Bosch 3/4 prong plugs, drive 100 mile to burn off all the factory coatings, then install the NGK IRIDIUM IX plugs. I tried just that a few years ago right after I purchased the X5. Did not looking on NGK website ordered the wrong plugs from a vendor due to their miss information. Completely different experience.

SPARK PLUG UPDATE- NGK ETC...
 

Greetings everyone-

I spent some time this morning on the phone with NGK headquarters discussing the proper spark plug for the BMW x5 (all engines).

The answer is NGK BKR6EQUP

They specifically do not recommend the bkr6eix as it is in their words- an inferior plug and fouls more often, and needs to be replaced no longer than every 20k miles.

The BKR6EQUP has a stronger electrode , comes gapped correctly at .032 and will last longer with better results all around.

By the way- if you see the #3199 before or after the NGK or BKR6EQUP, that number is simply a stock number used by the auto parts stores.

NGK Plugs and respective gap settings
 

That plug (NGK Laser Platinum BKR6EQUP Stk #3199) is the actual OE plug on the X5 for 3.0, 4.4, and 4.6is

On the 4.8is
Iridium IX Part No. IZFR6H11, Stock No 4294, Plug gap .044” (OE PLUG)

I updated the spreadsheet based on your conversations with NGK which I found interesting as their comments matched Champion's efforts to push for a "TRUCK" SPECIFIC" plug that had a larger center electrode to reduce erosion under continuous hard acceleration pulls such as found in heavy vehicles with little 3.0 engines :) and towing.
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NGK Plugs and gap settings for X5's (Updated 4/28/2020)

3.0
Laser Platinum Part No. BKR6EQUP Stock Number 3199 Plug Gap .032"*
Iridium IX Part No. BKR6EIX, Stock No 6418, Plug gap .032”
Ruthenium HX Part No. FR6AHX-S, Stock 94279, Plug Gap .032”

4.4
Laser Platinum Part No. BKR6EQUP Stock Number 3199 Plug Gap .032"*
Iridium IX Part No. BKR6EIX, Stock No 6418, Plug gap .032”
Ruthenium HX Part No. FR6AHX-S, Stock 94279, Plug Gap .032”

4.6is
Laser Platinum Part No. BKR6EQUP Stock Number 3199 Plug Gap .032"*
Iridium IX Part No. BKR6EIX, Stock No 6418, Plug gap .032”
Ruthenium HX Part No. FR6AHX-S, Stock 94279 , Plug Gap .032”

4.8is
Iridium IX Part No. ZFR6H11, Stock No 6441 Plug gap .044”
Lazer Iridum part No. IZFR6HFIX-11 stock No. 4294 Plug gap .044” (OE plug) *
Ruthenium HX Part No. FR6AHX-S, Stock 94279, Plug Gap .044”

I added the newest plug the "Ruthenium" that has some added burn enhancements and longevity properties. In the engine world nothing stands still. Technology is always moving forward.

* Actual OE plug

Note corrected info
4/28/20