The CarChip E/X with Alarm is a chunky block (1.4 by 1.8 by 1 inches) of translucent plastic with one side taken up by its OBD-II plug. It's small enough that it should fit into the OBD-II connector on any car without being hampered by tight cabin spaces. Davis, the manufacturer of the CarChip, does state that there are a few vehicles in which the device doesn't work properly, so you should consult the company's Web site before purchase. We put it in a BMW Z3, and it fit fine in the car's passenger-side center-stack connector, although it looked a bit unsightly sticking out of the smooth plastic covering. A proprietary cable connects CarChip to a PC's USB slot. The software for CarChip is functional but basic; it uses a spreadsheet format to display car data. It also lets you enter multiple vehicles, but CarChip has no way of identifying the vehicle it's monitoring. You have to remember which car it was logging when you download the data.
With CarChip E/X with Alarm connected to a PC, logged data can be viewed in the CarChip software, and CarChip can be set to monitor up to 4 specific engine parameters and reset the Check Engine light; plus, alarm thresholds can be specified. CarChip is a bit limited in that it reads only power train OBD-II codes, and it can be set for only 4 parameters beyond its standard 4 (it always logs time, distance, speed, and acceleration). There are a total of 23 user-selectable engine parameters, including fuel pressure, battery voltage, and coolant temperature. By default, the alarm is set to go off at speeds more than 70mph and hard braking. The alarm can be disabled, or the speed and deceleration thresholds can be changed. Unfortunately, the alarm can't be set to monitor other parameters, such as engine temperatures, which might prove useful.
CarChip E/X with Alarm performs exactly as it's intended, monitoring and recording all preset parameters. You can set the interval at which it grabs data, and at a wide interval, it can record 300 hours of drive-time data. Downloading the data to a PC is very fast.
Davis maintains all documentation on its support Web site, with complete PDF manuals. The support section also includes a useful FAQ with a link to an online database of locations for OBD-II connectors in different cars. E-mail support is available, as is a toll-free telephone number, which is available Monday through Friday, 7 a.m. to 5:30 p.m., Pacific time.