My S200 is very new and I am somewhat disappointed in that it is suppose to be the flagship and you cannot even adjust the overspeed warning it has built in 5% above the road map speed according to Navman Tech support.
You cannot even change the Map colours....
I just got an S150 to replace a Tomtom XL series 30 which was always stuffing up, even though under warranty I was so sick of it I just bought a Navman. So far very pleased with it, the Navteq Map software to me is much better, I love not having to put the suburb (when you're not sure which suburb), the free form searching is much nicer. It has a manual overspeed warning so not sure what the problem is with yours. Map colours well the maps are much sharper than Tomtom was so not really worried about changing the colours, only really a couple of colour schemes worked on the Tomtom anyway. The tomtom could easy take 5 min to get a GPS fix, sometimes never did. This Navman has it before I leave my driveway. So far so good.