After much back and forth I have endschieden for the GTB 8 A, pursuing him in Astra g of the size I was skeptical at first. The device hardly takes up space and beautifully understated by Bass ago. I connected the easy at cigarette but you can also easily connect to continuous positive because it after 60sec. off if that's too risky to take Zigarettena.
Conclusion:
Who wants to have a decent bass is hereby served best, who wants to make his car to Kasper Bude should have something bigger take in my case, I'm best served with the GTB 8 A's all I need!