I am looking at puting a puter in the car and want to have real time guages on a touch screen instead of the stock speedo. I have seen OBDII to USB cables on ebay.
Do I need a special cable or would a generic one do the job?
I have software, but want to know if any cable will work.

Thanks
Khoulongue
2003 cooper S
(planed mods, 17% gear, cold air intake, headers, flow through exhaust, and of course OBD monitor with full media server, for starters)

ps. Is there a way to talk back to the car to "tweek" the settings to get more horse power, etc?

pss. forgive if this post isn't in the right place, I am new. (I guess that after this I will know better and won't be able to use this excuse again).