Anything can void your warranty. But yes always take it out. And there is no reason why you couldn't install this yourself. Its literally a 20 minute job.
You have to order the usb from terrys site.
There are only two maps for the n55. Stock and map one.
2011 AW/e90/n55 email@example.com
I'm crawling similar to a ant cuz I'm low to the earth