The unit you linked has some interesting options. There's a TPMS package (including sensors) for only $169.

Options
ATSC Digital TV(US Canada Mexico Korea) +US$75.00
DVB-T Digital TV(Europe Australia India Africa) +US$45.00
ISDB-T Digital TV(Japan Brazil Chile Peru South-American) +US$75.00
Wireless Rearview Camera +US$35.00
Special Rearview Camera for BMW +US$40.00
TPMS +US$169.00