By this link:
It seems to me that the 1998 C280 is NOT on the "admissable" list.
Even if you can get clearance, you will need to modify:
Bumpers to 8 km/h standard.
Daytime Running Lights - The MB module is $$$$.
While that is a short list, it looks to me like it could cost thousands.
I still can't find where the 98 C280 is considered admissable, even modified.