I've scouted 4 models... in car accessory stores in Robinson & Sta. Lucia.
1. Concept, 2 sensor, audio, 1700
2. Red Alert, 4 sensor, audio, 2500
3. Can't recall the brand, a 2 sensors, with audio and stereo-like LED bar graph, with digital display, 3200
4. Goldeneye, 4 sensor, audio, with embedded display on rear-view mirror, 4500

Some has free installation, some with extra charges. I'm just concerned baka mahirapan siya sa pag-install sa APV

Will scout some more when I still have time...isip-isip.