If you built it out in the boot properly... so that the Xbox is stable and does not move then it will be fine,, you could also remove the game when you want to drive off... im guessin you want it in a different place to the boot? ... will be hassle if its in the front etc...... and why would you need it chipped?, would just like being indoors but in a car instead! ... and if you leave it standard you could get a wireless adapter... and i guess, when in a car park maybe you could open up the boot... try finding a wireless from a local shop or something and play a bit of need for speed .... sounds like a good idea, i was going to do it.. then realized there wasnt enough room to put a screen in my car boot