I just installed the 17555 exhaust on my 06 R. The 17555 is the newer version and it has 2 O2 bungs on the header pipe that the older 17535 does not have. The mounting is the same between the the two versions. I have Tmax so i use the O2 sensors for autotuning. You could still use this version and put plugs in the O2 bungs.
The bracket for the R is unique to the R and I did purchase the last one that V&H had. I think the bracket part number was 410-P. I posted up about this a few months ago in the R section.
The hardest part of the install is wrestling the header pipes into place...start with the front cylinder head and pull the rear in second.
"Buttercup" - 2006 Yellow Street Rod
"Cupcake" - 2009 Blue Buell XB12Scg Lightning
"Tutti Fruiti" - 2003 Buell XB9SL