stay away from Quicksand. Gary has shity customer service. i got a swinger from him and before i even got it on my bike the chrome started peeling, i have been trying to get ahold of him for MONTHS and he wont return my calls or emails.
for the 450 arms you have to grind a small portion of the lower mount i want to say, i cant tell you for sure cause iv never done it. search around, there are a few guys here that have done it before