Hey, before you killed that option, this is my opinion on the DSP. I had a 97 528i with standard stereo and I tried my friend's 97 540i with DSP. The DSP sounds much better, I repeat MUCH BETTER than the regular sound system. The regular stereo is not good at all, it is even worse than my Bose Premium on my Acura Legend LS Coupe 93. So, my recommendation if you didn't have plan to change your stereo, GET THE DSP, it is definitely worth it. I regret that I didn't find pre-owned 528i that has DSP on it, oh well. Hope you pick your option wisely.