My 08 a4 sline does not have a homelink garage door opener and i would like to install one. The audi home link visors are available on ebay for cheap.. does any one know if its all plug and play, is the plug on the harness the same , is the transmitter built in to the visor controls ? and are any other parts required .'I cant stand those clip on remotes...if someone gets in your car in the driveway they now have access to your garage