I looked into the bitten today and got a demo. Nice bit of kit but we came to the conclusion it wasnt needed with my RCD510.
First off for the bitten (and any of the DSP systems like cleansweep etc) to work properly you shouldn't use the volume on the headunit / steering wheel as this will mess up the de-equalisation from the bitten. Basically it works out how to correct the system at a certain volume level so if you change that level you then create a new eq that will need re-adjusting.
Also... on the RCD510 we worked out that below about 60% volume there was very little (if any) bass roll off. So just set your amp gains and LOC output level so that 60% volume on the headunit gives you the max volume you will ever need... Then you know even at the loudest comfortable listening level, you wont be into the territory where the headunit is messing with the signal.
Ontop of all this I have the LC2i LOC which has active bass restoration so even if i did stray into the volume range where the bass rolls off... the LC2i corrects this.
So basically the sales guy ended up agreeing the bitten wasnt really needed for my set up. Plus the bitten sounds a pain to set up as you need access to a real time spectrum analyser.
You may decide differently.
bitten = £300+
LC2i = £100 with the bass control dial (from america)