Welcome to the world of "custom" exhausts. I got a set from a different foreign company that were supposed to be bolt on and they bolted on fine.... after modification to the frame and indenting the header on the system...and reworking their heat shields!!.
Prior to this system I had a set of Jardines which ACTUALLY fit but they were damaged in an accident and they are no longer made. I did consider the Zards but just the visual alone looked like an installation nightmare!
The company from which I bought them said that they would fit my system to an actual bike before sending them and that they had, long ago, worked out the fitment issues. Either I'm smoking something or they are because they were a nightmare to fit.
Also, expensive as hell and the detail quality was second rate.
You are, probably, not missing a thing because a grinder was an integral part of my installation as well.
Have another drink but it won't make the angle grinder go away.
BTW...the end result was great. Don't give up.
