Not everyone wishes to have 2 radios in the car and all the related problems. The MIC-E which is accessible from TAPR also permits you to send a 300ms APRS burst at the end of each transmission when you are communicating with your buddies via a 2M repeater.
Of course, the repeater has to be equipped to receive the APRS packets into a TNC for buffering, and block them from the transmit side of the repeater and communicate them to the APRS channel by either direct wiring or via a common low power APRS station co-located with the repeater. The TNC can be set up to substitute the repeater's call sign for the RELAY wildcard in the original APRS packet if you equip the TNC at the repeater receiver site with a new, special EPROM.
We think it should be ok to hear that 300ms packet burst at the end of every transmission, it would seem just like a 'pong', but that most keen repeater users will not be too bothered about the same, so the best approach is to bar it from the transmit side.
The MIM is also adapted to work with a radio to insert your APRS burst at the end of your broadcasts, and it costs much lesser than the MIC-E which even though is very carefully packaged but turns out to be quite expensive after it is converted to the Canadian currency. The MIM has a 'hold-off' lead t sense to sense when your microphone PTT button is pressed and send its transmission as soon as you let go. You will need to ask your repeater committee to thoughtfully consider putting APRS over your repeater.