Join Date: Mar 2017
Location: Copenhagen, Denmark
I doubt you'll need any modification. Most aftermarket bars are simply hollow, which means you won't be drilling anything. The mirrors are with 'expandable bolts', which is not entirely the correct name - this means the rubber on the inserts will expand as you tighten the bolt, thus making them locked into place by friction. Often these types of mirrors will need a slight retightening along the way! :-)
Good choice on bar end mirrors - if you've never had them before, I am sure you will be extremely impressed!