My C43 AMG does not have a separate AMG maintenance/owner's manual -- the C class manuals (which came with the car) do have additional sections specific to the C43 AMG, but even C280 owners would have the same material in their manuals -- it just would not be relevant to their car.

See this link for E55 specifications and options (it may, however, only be relevant to the US models):

http://www.mbusa.com/brand/container.jsp?/overview/overview_engine.jsp&yearModelCode=99_E55&class=99_E&rnav=01234568&menu=4_3

The world-wide MB site: http://www.mercedes-benz.com/e/cars/e-class/lines.htm does appear to differentiate the AMG E class from the Avantgarde, which appears to be comparable to the US E430 Sport. The E430 Sport has badging (presumably similar to the "Avantgarde" on the side of your car) on the sides between the front wheels and the front doors.

My AMG gearshift says "Sport", and I have AMG-labeled white-faced instrumentation, AMG labeled oval exhaust tips, C43 AMG floor mats, AMG steering wheel with thumb pads and an AMG logo on the plastic engine cover, as well as AMG wheels. If it is like the US models, the car should have "E55" on the left boot face and "AMG" on the right boot face.

If you are missing many of these items (perhaps we can hear from an E55 owner), you may have only the Avantgarde model, in which case you may well have a claim for recission. In any event, you ought toi be able to feel the performance difference from an E430 sport.

As others have mentioned, I would not be concerned with the '98 build date, since '99 models came out in the fall of '98. There was not a '98 E55 (at least in the US).