car parking sensors - was Haigh venom a good choice?

[Guest]

I've just purchased Haigh Venom 8 sensor car parking sensors from Autobarn here in Australia. I'm having them fitted this Tuesday.

Reading the materials in the box, it says there is a digital readout for the front end of the car that says how far I am from objects. for the rear of the car there is a 3 stage alarm: 100 to 150cm safe mode alarm, 50 to 90cm is alarm mode awareness and 0 to 40 cm is danger mode.

It seems from the instructions that the reverse mode does not provide any distance indicator even though the front one does. This means that once I get within 40cm of an object while reversing I can't go any further without being sure I'm getting too close or about to collide. This seems strange to me since it would be good to know exactly how close I am to objects when reversing and I would have thought the final reversing alarm should be when within 20 cm.

Is this how good quality parking sensors usually work?

Will the car parking sensors still be useful in helping to manouvre in tight situations, even though I have to stop reversing as soon as I'm 40 cm away?

It is an auto car. If I want to reverse further when final reverse alarm goes off should it be safe to ease off on brake briefly once or even twcie to inch further back?

Is it easy to modify them so the final reverse alarm cuts in when only 20cm away?

I am interested in any other comments/thoughts from others on parking sensors, especially owners of cars that have them and how they work.