The "headless screws" or "rivets" you see holding the tower on the intake are a special Mercedes break away screw. Two new ones should be included in the new tower kit. They break off after you tighten them down to the correct torque, leaving what you see there now. You must find a way you are comfortable with the cut the old tower and mounting studs off. I recommend getting a dremel tool with a cut off wheel for aluminum. It cuts off fairly easily. Just do it being careful to get no filings in the intake below. You dont need to save anything of the old parts, so cut it off and not worry, it is all included in a new tower kit.
Why are you replacing it anyhow? Usually the only reason is a broken adjustment spring inside. If you do replace, consider not putting the metal sealing plug back in the top of the tower so you can get at the adjustment opening if you need. You can put a rubber vac cap over the opening if you are concerned about vac leakage. I have never had any issue with the sealing ball removed.

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Christopher Henkel
1990 190E 2.6 - Arctic white SOLD
1986 190E-16v - Blauswartze
1993 300CE - SOLD
2003 W208 CLK 320 Cabriolet - Magma Red