It's one of them, we're a lot of people would prefer the genuine stuff in the Renault box,But if you go for the likes of SKF, INA, Gates, Dayco and other timing belt kits to the same quality you will probably find they are what you would be buying from Renault and roll of the production line.
A lot of people will probably disagree with me, but this is one of the things I have learnt in the motor trade working for a factor selling the parts.
Another example is clutches, I know it's not what your asking but.. Valeo is The genuine clutch on a lot of French cars, do people will ask for valeo because it is genuine yet when an LUK clutch kit is offered they turn their noses up even though LUK will be putting the valeo in their box, LUK don't make aftermarket clutches, they what ever vehicle they don't make them for originally they will buy and put in their box, it's what a lot of manufacturers do these days.
So in relation to your question you could find its INA tensioners in the Renault box and a gates belt, and if you bought in the aftermarket it may be cheaper. But these days even the genuine parts really arnt massively more expensive than another make, some things are still hugely different in price others are not so different. I will just say stay away from cheap copy kits that don't have a major brand on them, if you go to a factor for a kit rather than genuine stick a well know make like the ones I've mentioned above.
Hope that helps.
