Interested in buying a scanner

[amg kodiak]

In the last couple of months I have become more and more comforatable working on my car (the AMG badge was scaring me away). I am now considering purchasing a scanner for the car. While the car does have ODBII, my mechanic told me that the car is not really an ODBII car and in order to diagnose the majority of the problems you have to have the older mercedes scanner (looks like a 4 x 6 x 1 inch black box with a 1 inch fitting for the link up and a bunch of pin receptors on the top. Is this true? If so where can I get one of the these scanners for a good price?

Thanks,
~dnm