my cousin runs a B5 with a stock 2013 pipe in his 6R and the other a 2058 with a B6 just fine..they just had to take some of the stone guard off there where it indents for the velcro strip nobody uses. no biggy..other than that it fits. It does however sit very close to the body because of this and they do get some body melting where the pipes get real close to the body. One used some heat shield tape that solved this issue...the other accepted them a battle scars lol. because of the 4 spring system the Werks pipes use, using the stock header pushes that whole connection just far enough that it touches the body on the 6R where it has that radius bart at the rear of the sidepod just infront of the rear mudguards....they just trimmed this part a bit more too to solve.
Myself, I use my O.S 2060 header drilled to fit my 2058. the O.S pipes are mugen friendly and i didnt want to get another header since I got the 2058 on its own without a header. fits perfectly with about 5mm to spare between the pipe and the side guard