Yeah, from 87 to aboout 92 the top of the line in sound was the Jensen Accusound package. I'm not sure what they did with the head unit, other than adding DNR (Dynamic Noise Reduction) and Dolby surround sound to it (I have one stock from my 87, which strangly did not come with the Jensen speakers), but they added better speakers, and 2 tweeters in the front. from what I've seen many XJs are actually wired for tweeters in the front. I swapped in a set of Jensen tweeters from my old 87 Pioneer. Not the best in sound, but they do make a difference, and they were free. I'm probably just going to end up replacing everything with Pioneer anyways.