Daka, since you can do eBay and computer, look up the romanian dude that sells an OBD cable and includes a set of BMW specific sofware along with the cable? go to ebay, search for INPA, a dude in Romania pops up, his stuff is about $40 or so... In order to use it, you will need to have a laptop computer running a Windows XP and thats all... the software will allow you to read the codes, reset the codes (most of the codes can be read, I don't think this software allows you to alter the car's mileage though)...

The convenience of the Torq and the smart phone would be the portability of the setup and no dangling wires, as the OBD would go though Bluetooth wireless connection to the smartphone...

but since your technological advancement stopped around 1990, we will push you up only 10 years to 2000, so an OBDII cable, and a WinXP laptop...