Kicker motor

I just bought a new boat that I am buying toys to rig up for walleye trolling on Erie. One major thing I need is a kicker motor. Ideally I want an 8-9.9hp mercury or Yamaha T8 but don't want to spend that kind of money, so that's off the table. I came across a good deal on a new Mercury 6 hp 4 stroke which would definitely provide sufficient power (18' approx. 1800 lbs). However, after reading about it, the general downside appears to be one cylinder motors are loud and vibrate a lot, getting on people's nerves and therefore increasing the potential for family fights. Is this still true with the newest 4 strokes out there? 
 
So I'm looking for some opinions on whether to consider a good deal on this brand new motor or continue to search Craigslist for a good used 8-9.9 hp, which, so far, appear to maintain their value better than any other boating item.
 
Thanks   

I bought my kicker of of Craigslist. Traveled 3 hrs for it. Make sure you're not just looking on your local Craigslist. Look at ones all around.

Mine stays clamped on the transom when towing. 8 hp 2 stroke on an 18' lund

'Rural PA version of Craigslist' = accurate description
 
Thanks for the reference, I wasn't familiar with it, might call about something on there tomorrow...

Andyg have info on a 9.9 but can't send you a PM.  Try sending one to me and see if I can return the info to you.