I had a little trouble getting used to the new DC infiltration system (but now I love it). I put this list together to help me and hopefully others. I haven't played some races in depth, so by all means corrections welcome (I'll try to edit and update).
SM
Infiltrate:
Scout*
Skull Probe
Detect:
Librarian
Skull Probe
IG
Infiltrate:
Vindicare Assassin
Detect:
Psykers
Long Range Scan (activated at HQ building; one scanner with timer per each HQ)
ELDAR
Infiltrate:
Ranger*
Webway Gate*#
Detect:
Seer Coucil
Guardian Sqauds (with Warlocks)
Harlequins
CHAOS
Infiltrate:
Chaos Space Marine*
Cultist*
Detect:
Cultist
Sorcerer
Chaos Lord (with Tainted Auspex)
ORK
Infiltrate:
Gretchen*
Tankbustas
Detect:
Big Mek
Warboss
Mega Armored Nobz
NECRONS
Infiltrate:
Necron Lord (and nearby units w Veil of Darkness)*
Detect:
Builder Scarab
Wraith
Necron Lord (with Solar Pulse)*
TAU
Infiltrate:
Devilfish Troop Carrier
Stealth Suit Team
Detect:
Vespid Stingwing
Path Finder
Ethereal
*Research required
#Eldar building: cloaking ability affects nearby structures
All Turrets/Waagh Banners Detect (Missile Turrets have slightly longer range)
All Captured Points-very small detection radius





