Hello, so I had a system installed again. So far the following is installed : Starterbatt : Standard Opel 55 Amps Additionalbatt : Optima Red Top in the trunk directly at the amps Frontamp : Steg K2.02 Subamp : Steg K2.02 Front : Audio System HX 165 SQ HU : Opel CD30MP3 Hi-Low : Alto Mobile UI-2 Hi-Low Converter So far I am very satisfied with the problem with front and everything and the whole sounds very fine. Now the question is which sub i am looking for on the b The fact is it should rather run out of 2 ohms impedance than 4 ohms, because I only have 600 W at 4 ohms and 1.1 kW at 2 ohms at all. There are many woofers to choose from. I would be able to get cheap at 1 x audio system CX-12 or 2 x audio system Xion 12. Both are older woofers but cheaper for that. I could probably also get a Rockford T215 cheaply, but I can’t really decide. What would you recommend? Play the woofers should actually play everything. Fast rock basses, deep hip hop, trance, etc. etc. MFG Alex