Experience with Grom USB3 for Subaru?

Hello people I own after my old E36 annoyed me recently a Subaru Legacy 2005 “Celebration”, and am also really happy with it, besides a fact: missing USB interface. The radio is with the controls one, since Subaru probably did not think as far as usual… Who looks in here knows the problem I think. That’s why I do it short: Does someone happen to have experience with the Grom USB3 interface? Cost 150€ and should make it to the radio it is a CD changer. L according to the functions specified by the manufacturer this sounds really good, you should probably choose CD changers, but then choose between the folders quite normally as if it was not retrofitted at all… 150€ is, I do not find, in contrast to other conversion alternatives not too expensive, and I have already looked, for my radio there are those. Or maybe there are alternatives? The following I have found out for myself what alternatively goes / should go: -A different aperture with all controls but a DIN- Schacht (I don’t like to exchange these controls for any non-original ones) -In addition, install the other radio, and disconnect the original one (but I think it looks stupid) So I wouldn’t like to use any of the alternatives, except the interface wouldn’t do any good. But then the question: Does anyone have experience with the (rightly expensive) aperture with DIN shaft?