The stock signals use two holes for mounting. So do the R1 flushmounts. They fit perfectly, and don't require any fairing modification (at least on my Lightning).
An ep-36 relay costs about 12 bucks, so that makes the total package of signals for front/rear + relay about 75 dollars. Well worth it, in my opinion. But be aware that the flushmounts up front on a lightning, because of their mount angle, make for almost useless turn signals. I like them because they clean things up and are bright as f*ck from the side, but when it comes to a head-on view (especially with both HID lights on), you can barely see them.