Looking to upgrade the original cellphone in my e39, how?

[Fernando]

I have a 1999 540i which came with the business package (hands free phone option). I want to use as much of the existing wiring as possible and ideally would like to get something plug a play where I can use an alternate cellphone ie: Motorola V3. I realize I will have to change the dock for the phone but what else (wiring wise) would have to change and what are the respective parts required.

I don't believe the existing cellphone is a GSM type phone, but I could be wrong.

I see there are some expensive oem bluetooth options, but I didn't want to go that expensive.

I'm also in the Toronto area so if anyone has any ideas (and associated costs) I would greatly appreciate it.

Thanks,
Fern