be careful as said, it could be...
nicked
or as said a group waiting to take the cash off you.
Personally I would go in 2 cars and atleast four - eight of you.
You and a couple of mates go to the addressin one car, car 2 waits round the corner, when you turn up, have a mate that is with you chattin to the other mates on the mobiles in the other car.
If it suddenly turns a bit hairy, he can tell the others and they can be with you in seconds.
Maybe a bargain, but I think there will be more to this than meets they eye.
Someone I know of bought a rolling shell, he turned up and went to load it up and the seller says, take it off, I want another 1k

all got very nasty, unfortunately for the seller, the guy who bought it looked like a pussy but was extremely hard and violent.
The seller quickly decided he didn't need the extra 1k after all