Yo KAK....if you use the supplied bars,you WON'T be able to use your STOCK ends...cause they fasten into the clip-on(stock)via a threaded insert already welded into the bar end.So it isn't going to make a difference WHAT bar end you go with(unless the Spiegler as you said slides in their bars and secures in there.Then that'll work...for THEIR bar ends.You will need the inserts(Acerbis or someone)to use any ends that require a threading bolt attachment.