Larry, I hope you don't mind but I am going to add some changes for those people who have convertibles. I figure it would be good to keep one thread for the install.
Installing the UUC front bar is little more complicated on the E88. To make up for lack of a solid roof, there is extra bracing all over the car. Looking under a convertible, you will see a V-brace with the point near the front bumper with the ends connecting to the outside of the body near the front jack pad. See #3, #4, and #5 in the pic below. You will remove these parts in addition to the parts Larry outlined in his posts. First remove the cover (#5 in the pic) that protects the bolts where the 2 braces meet to form a 'V'. Then you will remove the other nuts holding the brace (there are at least 2 more per brace). Note that I was also installing the //M tension rods. Having removed those, I will able to remove the front brace bolts and loosen the brace middle bolts and slide it out. I think you will have to either remove the tension rods or the bracing. It will be easier to remove the bracing if you are not planning on installing the //M tension rods.
Another joy of having a convertible is having take out 24 freaking screws to remove the front plastic pan. The coupe guys get away with "only" 18 screws. Lucky bastards.
I have the redesigned UUC bar on full stiff. I will test it out at the autox next weekend.