to the bmw world, and the forums
as to your gas question! u should use 89 octane or better... i use 93 in my car!! she loves it!!
the chip, everyone is talking about is a computer chip which is put into your car and remaps the gas and increases hp, and gets rid of the top speed limiter of the car... u can find them all over the place... i personally would buy them from bavauto... its about 300 bucks.. but its well worth it
about your seats... sure u can allways buy new 1's or u can have them re-leatherd.. which ever u prefer!!
again... enjoy your stay!