A pair of JBL Stage 600C speakers arrived and were fitted today and I can confirm they are worlds apart from the originals. Fitting was fairly straightforward, the old ones are held into the plastic mounts with bent tabs and I drilled the mounts to use the supplied self tappers to fit the new ones. I tried the JBL tweeters that came in the box and, they didn't sound any different to the originals so I didn't use them although once out of heir plastic housings could have been fitted if I'd wanted to. Bass response is a definite improvement, I can use bass boost on the DSP settings in the head unit and it actually does something which it didn't before. They sound pretty damn good to me although I think I still need a sub.....