pre-owned E46 M3 -- questions

[crosvs]

Hey everyone-

As some of you probably read, due to the ongoing problems with my aging (115,000 miles) X5, we are strongly considering trading it in for an E46 M3.

The most important thing is that:

* it must be convertible

* it MUST have extended warranty (100,000 miles / 5 yrs?)

* i would like SMG *IF* it won't be a maintenance nightmare like other electrohydraulic manuals (Ferrari, Lambo, etc.)

* it MUST have GPS satnav

* has upgraded HK audio

From my preliminary research, it seems like it should be possible to obtain an 04 or 05 model for the low $40Ks ... agreed?

ALSO: if buying from a NON-BMW seller (e.g., indepenent dealer, private party, etc) ... can I take it to BMW to extend the warranty?

Finally: I understand that early M3s had blown engine problems, but I think this was remedied after 2004 year models. Correct?

Thank you!!