I replaced my rear shelf set with Rainbow components today. It was very straight forward due to
rs32's excellent write-up and fitting instructions and took me around an hour to do
It took me a few goes at deciding which way round the connection should go as there didn't seem much difference between +/- in either position? The Rainbow units were also much quieter than the OEM ones for the same volume setting! I settled for the slightly louder/deeper one in the end. Maybe my Alpine head unit affected this but not too sure...
Due to the above paragraph, i was sceptical of just how much difference it would actually make, but i'm pleased to report that i now have some bass and depth of sound in the car for that
rare occaision when you want music rather than 'straight-six' to listen to!
It's particularly noticeable when you fade the speakers front to back and you realise just how pants the BMW OEM ones are!
I will certainly buy a second set now to complete the setup and improve one of the CSL's few weak spots. Just need to psyche myself up to remove the CF door cards...