Hey, Mike -
In my Shop I had in WA., I had hundreds of BMW's alone to Detail, and I either used a really strong cleaner if they were really, really, neglected, and black from never removing the brake dust, or, if they were maintained even on the back sides, I would just use regular car wash soap. The stronger the cleaner you use, the more your protection will be compromised and even removed completely..
The one Car Wash Soap I have been using for a few years is Chemical Guys CitrusWash Clear..
It has great suds, cleans really well, and is not finicky, high maintenance, or anything like some products..
For a good maintenance cleaner and sealer for wheels, I have found Rejex to be pretty darn good and the price is very reasonable.. Here is the link -
Rejex Paint Sealant, wheel sealant, plastic sealant, durable paint protection
No Sealer out there is going to last a long time on hot wheels that are being bombarded with hotter brake dust. Some might last longer, but this is again, a very subjective subject..
Guess if Consumer Reports ever lined up a few dozen wheels, and in a Lab, cleaned them and then got them dirty again in controlled environments, and then cleaned and measured the Sealant protection, I might be a little persuaded to try something - only after a lot of other people did first..
Your approach to all of this and mileage may differ..
If you want to go all out and do some major cleaning and then a really good protectant, I would then go to a Coating..
Coatings are way more expensive but if they are good and applied perfectly, well, you will not have to do much to get any dirt or brake dust that manages to stick to them off..
And these same Coatings are used on the rest of the Paintwork of the car as well...
Preparation for a Coating is much more involved, and you would pretty much want to get all defects out of the paint before you Coated it, if you decided to really get into this..
Once you get the wheels to the level you like, just wash them with car wash soap and it should be enough.. Remember, they are painted and clear coated like the paint on your Bimmer...
And lucky for all of us , there are special wheel shops that can repair curb damage, etc., and repaint wheels, etc., back to better than original...
Good luck !
Dan F