Went to Auto Sound & Security in the Bay Area today to purchace the Ungo 8300. However the sales"kid" thought I might be happier with a Clifford Concept 400. It has the Dual-zone Proximity Sensor instead of a shock sensor. He informed me that Clifford was a little more expensive ($450 installed) than the Ungo. Does anyone have strong opinions on Clifford vs. Ungo?