I have the SAME EXACT problem and was going to ask this, the parent thing is easy to get past, well I mean unless your really untrustworthy (wouldn't be the case if your a kid/teenager like me and they can trust you with a BMW) no parent looks under the hood. Warranty is another thing but it comes with the territory with ANY decent modification to a car, besides and e90post.com sticker +10hp to the wheels yo
.I would definitively get a supercharger if it came out, but a turbo charger I would wait a long time before I got one.