You can keep the stock mirror stalks and just replace the mirror heads. I bought a set of Yamaha take-offs from a Warrior for $20 and they have a much better field of view due to their shape. The aftermarket mirrors tend to blurr easily, such as the Kuryakyn magnums. Whatever you do, don't get mirrors with flat glass...they are useless. Make sure they are convex style to prevent excess vibration in the view.
Any metric mirror head should work if they are the 10 mm threads...good luck.