I just ran mine down the stem and attached the fused link to the battery.
I've got the 450, had it for well over a year now. Didn't need or want the XM radio or traffic radio options-which still cost even more to add and more to subscribe, on top of an almost $200 difference between the 450 and 550 to simply allow the add ons-and it works great.
Though recently it insists on taking me on back roads and avoiding highways, it's been doing this since after the last firmware update. It's set to "faster time" but on a recent trip to Sacramento it shoved me thru 6 miles of back roads to get to a hotel instead of taking me up the freeway two more exits where the destination was less than a block off the freeway. I'd taken the same trip once when the device was new and it properly guided me along the freeway route instead of the tour of the industrial/wrong side of the tracks part of town.