The hose from the turbo oil sump connects to the air filter housing, not the intercooler. Connecting it to the intercooler would put it under pressure when the engine is on boost.
Removing the oil cap does not affect the idle on a 930 like it does on an SC.
Kokeln's web site should have some info for you I would think.
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