I've had my BSW kit for quite awhile now..
My main reservation has been where they suggest you mount it.. I don't like it. By the spare and zip tied didn't appeal to me.. Plus I have the pull out luggage loading rack which is rad except there's 2 layers to deal with to get to the amp.. So here was my solution.
I have deleted the cd changer with dice duo and spec deck.. So first I used the changer and mounting brackets for measuring.. Putting the amp on top of the cd changer/ between brackets..



Btw here's the aluminum stock I used
So chop that off, put it in your vice and use a rubber mallet to get a 90 angle. Be sure to have the mark line about 1-2 mm to allow for the bend.



Next your going to want to drill your holes with a #29 bit so you can use a hand tap (you can get these kits at Home Depot etc.. ( on the BSW amp your going to want to drill a center hole for the side plate and measure about back 1/16 off center for you amp ear to clear the arch on the BMW mounting bracket.

. Whoops!
I think I've out used my uploads.. So I shall reply and continue...