You're going to get as many opinions on this as there are brands of slip-ons, maybe more. Listen to different bikes with different exhaust set-ups and find one that appeals to you.
i just put a set of Full Boar's on mine. I love the sound and for $199 for the pair it is pretty hard to beat. Nice low rumble and then they bark when you nail it. Also very impressed with the fit and finish of the chrome.
CFR's.......The ONLY problem I have with recommending them is that they are not well known yet. With the CFR slip-on pipes my bike stands out around other bikes. Definitely not another cow in the heard.......I'm my own cow!!! But to each their own. MOOOO
The ones I have on NOW, or was it the ones on the old king? Maybe the ones
on the not so soft, softtail, oh hell the jury is still out...........Tenn.Vol.