My engine is similar to yours.
Euro CIS, 112 WUR
You do not need any added fuel or ignition.
You do need to connect the Vac and Boost hoses to the WUR.
If your fuel mileage is bad (less than 18mpg highway) you likely need to adjust your WUR or clean your fuel head or both.
Wild guess is that your CO is high and you are running rich.
RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8