Don't know if they are any good, surely expensive, but Murray Motors is certified to do Escort 9500 Ci installs (Beltonics). I'm sure they can do the StiR Plus. Worth a look, perhaps.
'09 E92 ///M3 | Jerez Black/Black Leather | Sycamore Anthracite | MDCT | Premium/Tech/Cold Weather Packages | 19" | Moonroof | Enhanced Premium Sound |iPod/USB | Smartphone
'97 E36 M3 Sedan Hellrot Red/Black; '03 E46 330Ci Met. Gray/Black; '06 E46 330Ci ZPF Imola Red/Saddle