The BMW Teufelkatze (Pg71) lists for standard equipment "Signature Dampening." The flavor text did not provide contextual clues other than the word "electronic." There is no "Signature Dampening" listed in the modification rules. There are, however, 2 mods that it could possibly mean: Signature Masking, or Electromagnetic Shielding. The only contextual clue is the lack of a listed rating (Signature Masking is available in Ratings).
Does the German Edition provide any insight?
Edit: My initial post incorrectly labeled one mod as "Signal Dampening."
It does. The entry for the Teufelskatze in the german book:
Standardausstattung: Diebstahlsicherung 3, Signaturmaskierung 2, Spezialausrüstung (FlashTech in Frontscheinwerfern und Rücklichtern)
Spielinformationen: Das FlashTech-System funktioniert wie ein Flash-Pack (SR5, S. 437) mit 10 Ladungen pro Scheinwerfer bzw. Rücklicht. Statt des normalen Elektroschocksystems hat die Diebstahlsicherung ein Flammenwerfersystem, das jeden in Brand setzt, der sich an dem Fahrzeug zu schaffen macht. Der Flammenwerfer verursacht 10K Schaden mit DK -6 und hat 10 Ladungen. Das Nachfüllen kostet 500 ¥.
Which translates to:
Standard Equipment: Anti-Theft System 3, Signature masking 2, special equipment (FlashTech in front and rear facing lights)
game information: The FlashTech-System works like a Flash-Pack with 10 charges per light. Instead of the usual electroshock system, the Anti-Theft system is equiped with a flamethrower, that will incinerate everyone that tries to temper with the car. The flamethrower has a DV of 10P with -6AP and has 10 charges. Refills are 500¥.