Hi - hope someone can help? This thread relates to my 98 B5 A4 saloon which is fitted with the standard non-Bose concert tape/radio, no cd changer and the active rear speakers. Basically I am trying to determine the difference between any built in EQ (if any) between the standard Audi Concert tape radio and the BOSE version. I am led to believe the BOSE version is the same unit but simply re-programmed through VAG-COM to work differently. As a bit of an experiment I plan to install a connects2 ipod adapter through the the factory CD changer input, upgrade the speakers, add an amplifier and maybe add a subwoofer as well. I can easily use the rear speaker output which is already low voltage output and then convert the front speaker high level output to low level, to feed the relevant amp(s). But - am I better of sourcing a Bose programmed unit before I do so? I have been trying to determine if aside from the on-screen 'BOSE' display and voltage outputs (ie I believe all four speaker output is non amplified and low level on the BOSE version) if the Audi and Bose versions have any preset EQ curves built in. Many people suggest that the BOSE programmed units have a 'flat' output which in my mind will be better to feed an amp. It seems the BOSE amp does all the equalisation and I dont plan to use the BOSE amp! I have also read the standard Audi versions have a sort of low volume 'loudness' function which diminishes as the volume is turned up? I can't verify either of these facts but it would seem a waste of time to go to all this work if the bass diminishes as the volume increases! Getting the unit reprogrammed should be a dealer option but if I pay to have it done and it doesnt work or sound better then I'm going to have to pay to have it put back! My dealership have said they have never reprogrammed a Concert head unit and don't know how to do it. I was asked to get a guide from the Internet and they would book the car in for one hour at a charge of £80 plus vat and hope they could get it done within the hour - no thanks! These BOSE versions command a high price on eBay so trying to pick up a cheap second unit to experiment with isn't an option either. I have read that on some Bose head units there is a Bose pin out which if earthed will set the radio to Bose mode? Has anyone done his or can anyone tell me if the sound quality from the concert after amplification is worth the effort? I have some experience fitting head units, speakers and amps etc so willing to have a crack at pretty much everything. Fitting a spangly new head unit is the easy option but for this car I really like the idea of a stealth/oem look. Thank you for reading Stu.