I have another question...
Are there any products out there that i could spray on my alloys (at the car wash) which will totally loosen all the brake dust so i can blast it off.
My alloys are a PITA to clean, so many spokes and little gaps to get in when doin them by hand 
yes... autosmart smart wheels or bilberry wheel cleaner - however... you would be well advised to do the following
spend TIME cleaning the wheels manually... with a decent brush... you could do this with smartwheels/bilberry
then WAX your wheels with poorboys wheel sealant/collinite/a.n.other hard wax - spend time doing this with a couple of coats.
you can then easily just spray a non-acidic wheel cleaner such as those mentioned and wash off without the need for scrubbing... the brake dust will find it more difficult to adhere with the wax one
btw - your paintwork won't be thanking you for using the swirly brush at the garage jetwash
