I have a 2001 LS 430 from Japan, ie which was made for the international market. Hence, the navigation is in Japanese. The car has aMark Levinson system and speakers and I am based in India where we don't even have a Lexus dealer or service station. The issues I have are below

1. The AM/FM frequency is not enough to play the FM channels here in India
2. I tried connecting a Pioneer DEH 4490BT with the speakers and it would not work. I chose the Pioneer as it allows me to use digital music, stream using bluetooth, sync with my phone, allows IPOD / USB usage. Further age of CDs is slowly out and we are all digital. The ML system has a 6 CH changer in the lower half and the radio and volume controls in the upper part.
The car audio dealer says that I cannot just change the system, I'll have to change the speakers too as ML has an inbuilt amp in the speakers and the Pioneer system has an amp too. Hence the two cannot live together. My idea is to just buy a good digital music system and connect the same to the ML speakers in the car. Is this possible and is my dealer just trying to sell me more or do I have to replace the speakers and the system as well at the same time?

I request all to guide me here. Thanks a lot for your help and time in advance.