Sorry to say it but lags do seem to be rather breakdown prone. You look at these forums and you will find plenty of people suffering with their lags.
Renault didn't put a lot of thought into many of their cars I'm afraid.
The only time you will get a good renault is when it is one of their most expensive- the avantime or the vel satis for instance.
Even my safrane is an exec car and cost £28.5k new. That has a few problems at the moment too (also including a snapped
spring but it isn't causing a serious problem at the moment) but the overall quality of it is far superior to our megane which is out the back with a knackered head gasket. All cars go wrong, but unfortunately Renaults 'cheaper' cars are very cheap on quality. They're not the easiest of cars to work on either as they're not really designed for easy access to parts.
My neighbour drives a 1973 VW beetle. He can fix every single part on it quite literally. Unlike a megane for instance, with onboard ECUs and all sorts of other bits that have to have a renault computer plugged in.
I'm afraid renault aren't the best cars for reliability..