I generally use the RTV black - but most of them work well for oil resistance. Just clean the area well and lay down a solid bead - about a 1/4" or so - and carefully install the intake. Be sure to coat the bolts with a sealant as well. Permatex makes a good product for that - keeps the oil from wicking up and leaking through the bolts.
I personally like to take a paper towel and wipe both ends immediately after installation. It looks better and makes sure the silicone is fully embedded in the gap.
