If you are talking about using it on a Surface RT, then it won't work. Ever. If it's Windows 8 (i.e. not RT), then it will work just fine. It comes down to 2 issues: Is the USB driver supported on Windows 8? Do you want greasy paw prints on your tablets screen?
Karl, windows 7 has an inbuilt XP mode, if windows 8 does too, I would personally use the surface or surface pro. Would be great to use while working on a car like you intend. Heaps easier than using a laptop anyway. I have always found it a pain using a laptop in a zed. You will be able to claim it on tax too as it will be for diagnostics etc.
The USB port on a Surface RT works just like any other USB port. Its fully functional. All that is needed is an Win RT Nistune App.
Which isn't available yet I use a gigabyte pro with win7 - I use a mouse so that I don't get the paw prints - but it gives me all the gauges, so I find it handy as well as having internet access on the move
We have a quite a selection of tablets and smart phones in our household. Over Christmas the series 1 Surface RT was on sale for $220 so I bought one. I have to tell you, Its an awesome tablet which I find much better than the IPads and Android phones we have scattered around. USB port that can play movies via USB stick, SD slot ( I have 64 gig card in it), multitasking Operating system. Ability to pin web links to the start screen. Its great..... So unless you used one, best to reserve judgment rather than listen to the endless tripe on the internet about how crap it is. If there was a Nistune app for it, it would be a winner for in car computing. BTW you can get the Start button and Desktop screen which looks just like Win 7 with one button push using Windows 8.1. In fact you would be going to notice it is different and looks just like a PC in this mode and has Office loaded as standard.
Really, damn, missed it, would have bought one for that. Where abouts? My reference to W8 being crap was more the full Windows. I work with this all day everyday. My business provides product and support for Microsoft networks, with a large emphasis on Office 365. I have not yet sold a single Windows 8 computer lol!