Premptively replacing the Timing Tensioner

I may have to buy a 2008 Mini Cooper S, or if I'm lucky go with the 2011 model. Of course the stories I hear about this problem throw a fly in the ointment. Otherwise, I really like this car. The 2008 that I had safety checked had no problems on safety check, but I'm wondering if folks premptively replace timing tensioners to prevent timing chain problems to begin with. And also, an unrelated question:  Ehy would Mini mount their engines with a plastic mounting frame? (or whatever that is) Critics point that out...but I'm sure they are just hating on the daring and stylish.