ET 20 Offset wheels on 06 e53 X5?

[Cadesto]

I posted another thread which hopefully I deleted successfully as to not flood.. Had a question answered but didn't really ask the right stuff..
So I bought a buddies 20" Beyern Spartans 9" front, 10" rear. They were mounted on his X6 for about 2 weeks, looked bad a** but he found new ones he wanted already lol..

He thought they were 35 offset. They are stamped ET20... Now I am to believe this means offset is 20 correct?

My confusion continues with the Beyern website. Www.beyernwheels.com

Which states:
Front: 9" available in 15, 20 and 32 offset. 20 having a 74 bore (15 and 32 having 72 bore)
Rear: 10" available in 20, 25 and 35 offset. 20 having a 72 bore (25 has 74 bore and 35 has 72)

Now on there website the offsets are under a column named "PCD" under the "ET" column every wheel is listed 5/120 which I know is the bolt pattern..

The tires I plan to run are 275/40/20 and 315/35/30 staggered....

So really my main questions are is the ET20 marking on the wheels the offset?

If so is 20 offset way to extreme? I used a calculator on 1010tires and measured with my calipers and it seems the rears will be about flush and the fronts may stick out a few millimeters, which is fine I like an aggressive stance. But all in all I'd rather not look like a dumbass...

I can't get my calipers inside the wheel and expand enough to measure the bore so I figure ill order some hub centric rings to be on the safe side if front or rears end up needing them.

I've attached 3 photos, #1 the wheel (love the pattern!) #2 inside front markings, #3 inside rear markings...

Any help figuring out the true offset of these wheels along with opinions and other wisdom is highly appreciated!!! Thanks in advance! Phil