the sad thing is many of the great dealers have closed their doors. Among them, Monicatti Chrysler in MI (one of the oldest Mopar Speed Shops in the country) I believe has closed, although they may still be selling select Mopar performance parts. Westoaks Dodge (another old SpeedShop)...and Riverton Dodge in WY (a small dealer with a kind staff), and the last US dealer I've dealt with, Birmingham Chryser (a 5star elite) With this said, there are a few good dealers left. Roanoke, West Herr Chrysler in Buffalo, Mike Patton Chrysler in GA, Moss Bros Chrysler & Don-a-veecin Dodge CA and Tallahasee Chrysler all come to mind. I've either had a good experience, or knew someone that has at each one of these. A search on dealerrater would probably yeild some positive feedback
The same can be said in Canada, Midway Chrysler in Winnipeg was an over all great dealer that I heard recently closed. But there's still a few places to get good service when buying parts etc. In Canada, Peel Chrysler in Scarborough Ont, Clare Dodge in NS (they're tiny, so don't expect a large parts inventory), and Kelowna Dodge in B.C all offer good service and a helpful parts staff.
Understand that for servics/repair work on Vipers, small dealers might not be the way to go, although I love small dealers when it comes to buying parts etc.