I replaced a key on my 07 E92 335i (same keyfob as the E70) for around $120 straight from the dealership back in 2008. I ordered it and about 3 days later it came in and did not need any programming. All I had to do was put in the the key slot, wait a few seconds and then start the car. The key was programmed by the car and I have not had any issues with it. For me to order the key I had to show proof of ownership (title or registration). I just called my dealership (which is typically overpriced) and they quoted $172 for the keyfob and the laser cut key that slides in.

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'12 E92 M3 ZCP Stage 2 Tune, Exhaust, Test pipes, GTS DCT Software
'07 E70 4.8i
'07 E92 335i FBO+Meth M3 Suspension Swap and much more 505hp 564 lb/ft tq (Sold)
'89 E30 325i (Retired with 230,000 miles )