If your 16", 8-hole wheels have the original 95mm lugs, they will stick out beyond the face of the Evo wheel. You'll want different lugs. The "correct" ones (approximately 70-75mm total length, with decorative cap) are NLA from MB but are available used. MB sells generic lug bolts only now, without the decorative cap, ~60mm long. These will work fine but won't be flush with the Evo wheel face. Totally depends what you want aesthetically.
The 16x8 ET34 wheels can work on your E320 wagon, but may require fender spacers and rolling the fender lips, particularly if the car is lowered.
Click here for the AMG wheel install docs of a similar width & offset, you may be able to avoid some of that work with careful tire selection.