I had one of these fitted and a Pure Highway 400. The modulator hardwires in so there's no hiss or interference (only time there's any issue is when the Highway itself loses signal).
https://www.ebay.co.uk/itm/274626379...hoClGAQAvD_BwE
The Pure controller fits nicely in the cupholder (didn't like it stuck on the dash). Its not the most elegant system for streaming but it works fine - I only stopped doing it because i found I could stream directly via the car.