i got an 05 x3 with premium sound system im trying to get (2) 12`s with an amp install but the local places around here doenst want to mess with it. is this common for bmw that nobody want to work on it?

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07 BMW 335 E90 (Procede & M-kit)
04 HONDA PILOT EX-L
79 MAZDA RX7 GS
street ported, nitrous rotary engine