Red key.....absolute must.
Service records....did I mention service records? Make sure everything was done by the book by a qualified mechanic. Never take sellers word for this.
Get it checked out by a mechanic to make sure it wasn't previously wrecked and check of mechanical condition.
I have an '03 620, it's been a great, reliable, and thrilling piece to own!
I would never buy a Duc without following these 3 golden rules.
thats pretty good advice! I agree with all this! Also look for abike with the usual mods already done (exhaust, ecu, airbox) These will cost you $1000+ on top of the price of the bike...you know you want that sound!!!!