Having tried the 4 in 1 ones & chucked them, I went with genuine Nokia full car kits in both of our cars.
They are dead reliable and work very well indeed, in fact they also fit the same ones in our works cars and I canvouch for them working at something in excess of the National Speed limit
lol:
Got both mine off eBay for no more than £40 each.
Dead easy to install too - locate a 12V live and an earth and the rest is just plug & play!
Andy